Fast Attack Choices: Here comes a unit-by-unit review of the Fast Attack choices, and how worthy each unit and upgrade is, plus how to best use each unit in your Tyranid army.
Tyranid Shrike Brood: These flying Warriors are identical to before, with a points drop. They are still vulnerable to Instant Death, and also have a Guardsmen save, but multiple wounds and their speed means they are pretty tough in cover.
Flesh Hooks: At a bit less than 5 points, you get frag grenades and 2 strength 4 shots, at 6". This isn't bad but Devourers are better. Cheap is the new black with Nids, so pick carefully, but Flesh hooks are good for killing that powerfist first. (6/10)
Toxin Sacks: Standard poison, always good. These don't do THAT much but they aren't too costly. If you want to kill stuff up close these are good, and Shrikes are meant to assault units. (6/10)
Adrenal Glands: Better than Toxin for the added fleet, but pricier. You should be able to get close enough with their jump move that this isn't a must. (5/10)
Spinefists: 3 TL shots strength 3, or Devourers? I'm inclined to go Devourers for superior range even if you miss out on ap 5 (Ha.) They aren't bad, but 12" is too short. (3/10)
Deathspitters: +1 strength, Ap 5. This will increase your killing power by a lot, which is always a good thing. But, Shrikes are served well by an extra CC attack. (6/10)
Scything Talons: Exchange 3 strength 4 shots for an extra attack, this isn't bad, but there are better options.(5/10)
Rending Claws: If one must go CC, this is how. Cheap, and can kill 2+ saves. This is pretty good if you do go with Shrikes. (7/10)
Lashwhip and Bonesword: This is super pricey for Ap. 3, honestly it just raises the points on a fragile platform by too much. (5/10)
Boneswords: Like above, but slightly cheaper, and now slower. Not bad, but gets pricey. (4/10)
Barbed Strangler: A cheap large blast? Why not? But, consider that your shrikes will now no longer be running. Not needed for a CC squad, but only missing one attack if you take it. (6/10)
Venom Cannon: I wish this was better, but at strength 6 small blast it can't quite kill vehicles or infantry... take the Strangler if you want a gun on Shrikes. (4/10)
Overall: If you lack forward synapse, these guys can be a good cheap assault and support unit. Unfortunately they are very fragile, so be prepared to take an indirect route to assault where they jump from cover to cover. But, remember that options don't have to be the same for each model and you can hide some real killing power in there! (5/10)
Example: 3 Shrikes, Rending Claws 105
5 Shrikes, Toxin Sacks, Flesh hooks, Scything Talons, One set of Lashwhip and Bonesword 205
Ravener Brood: These snakey guys are very similar to Shrikes statistically. Trade synapse and wings for the Beast type, which includes fleet. These guys are hard to take because of how similar they are to Shrikes. Their main selling point is in +1 initiative and the ability to move through terrain without any consequence to movement.
Rending Claws: No loss in attacks, but now rending. Raveners are essentially a pure CC unit, so this is an essentially mandatory upgrade that lets them threaten any unit and isn't very costly. (8/10)
Spinefists: At very cheap, you get a 3 shot TL gun. This is less than a gant, but won't likely be used as Raveners should be running or assaulting almost every turn. However if you have spare points, this isn't bad for lots of extra shots. (6/10)
Devourers: The damage here is almost identical to Spinefists, but costlier for extra range. However, I wouldn't make the investment. (4/10)
Deathspitter: The most powerful gun available is potentially quite deadly, but because you want to run or assault, I feel 10 is too many points to invest in a gun you may or may not use. (3/10)
The Red Terror: This guy finally got put back in the book, and is a very interesting character indeed! 6 attacks on the charge at WS 6, but no rending. However, if 4 hit (average on what is often a 3+) then you simply can remove an adjacent model who isn't Very Bulky or Extremely Bulky. This is great for nuking that Terminator armor character, but they do get one Invulnerable save to survive. However, he's very costly, almost the same as 3 Raveners. Since many current "good" armies don't have strong melee characters I don't think he's a must have, but he gets bonus points for the fear factor (NO ONE will want to challenge this guy, just in case their super special model gets completely removed.) and for how cool his rules are. (6/10)
Overall: Raveners are tricky because they're similar to Shrikes with no Synapse. If you take them, they have one role. Barrel towards your opponent, ignoring terrain, and multi-assault and kill a ton of units if they aren't dealt with. But, make sure there are some other units available to get in the way, as they will be a top priority for any general. These need a list based around them, as on there own can be shot to pieces. (7/10)
Example: 9 Raveners, Rending Claws 315
Sky Slasher Brood: If you happen to like the Forge World models for Flying Rippers, then I advise you to look at pictures and not buy them. I hate to be pessimistic, but this unit is just that bad.
Spinefists: Ok these aren't that bad I guess. A lot of shots, but not accurate and strength 3. Even twin-linked they'll miss a lot at BS 2. (4/10)
Toxin: Yeah, poison. Lots of attacks, but making a t3 multi-wound model pricier isn't good. (4/10)
Adrenal Glands: Fleet is pretty useful here, as at least they can make CC, seeing as they can do nothing else. No shooting, no scoring, they're a distraction. (4/10)
Overall: Ugh. These are point-for-wound equal to Gargoyles, but with ID, less attacks on the charge, lower WS/BS/I and no gun base. They're a fast tarpit, but all the units you'd want to tarpit would be even worse off against gargoyles. This is sadly a case of a unit priced the same as a unit in the same slot that does everything better. However, if you have the models, then try them as a cheap tarpit hugging cover until you surprise a Long Fang unit or such. But, MCs will ID these guys, so watch put for that... ( 2/10)
Example: 5 Sky-Slashers 90
Gargoyle Brood: I loved these fellows in 5th edition but never squeezed them into my lists in 6th... this was however more a product of my design than the unit. A great unit before, they had blinding venom changed to a single poison 6+ attack with blind, and had their upgrades increase in cost.
Adrenal Glands: Fleet makes these guys scary-fast on the assault. This has merits if you want to hit a unit in the face turn 2, and strength 4 will make vehicles run for the hills. (7/10)
Toxin Sacks: Poison makes these a fast unit that can hurt anything, but remember their role. If you want that role to be MC hunting, here's your stop. (5/10)
Overall: The most important trick to using these guys is to give them a single role. If it's as a screen for cover, don't make them too pricey. But if you want a fast cheap assault wave, try giving them one or the other upgrade (I think both is too much). They can hunt MCs or Vehicles, and are an amazing screening/tarpit due to their size and speed. Remember that EACH model has a blinding attack, so if you hit with 10 attacks, then your opponent must take 10 blinding checks! He won't break out of that combat any time soon... I think the goal here is to get a cheap fast wave of lots of bodies... the more models in the unit, the better! (7/10)
Example: 30 gargoyles, 180
30 gargoyles, Adrenal Glands 240
Harpy: This guy is the old 5th edition FMC who was overlooked first for lack of model, and now for the unit he shares a kit with. How deserving is the "little brother" of the Tyranid Flying Monstrous Creatures? He comes stock with a Twin-linked stranglethorn cannon, and may drop Spore Mines as he flies over units. Also, he halves the initiative of any unit he charges, so watch out for any multi-charge opportunities.
Twin-Linked Heavy Venom Cannon: For the price of one gant, go to a Strength 9 blast? Sounds great! But, remember what role you want the Harpy to have... The Cannon means he has little ranged anti-infantry and isn't great vs Vehicles... if you want to go this route, have a plan (Biovores) for enemy infantry at range. (6/10)
Stinger Salvo: Adding 4 strength 5 shots for a few points is not bad at all, and can help glance a vehicle or kill those last few wounds. This is hardly a must-have, but if you have the points, why not? (6/10)
Cluster Spines: Adding a Strength 5 Large Blast? I like it! This combos very well with the Stranglethorn, because two blasts are better than one! (7/10)
Overall: Just have a plan for this guy. Either a Venom Cannon for hull point reduction at range, or go double large blast to murder infantry. Yes, he's a fragile cannon, so always touch area terrain and try to present bigger targets to your opponent, but he is actually a very useful unit. (6/10)
Example: Harpy, Cluster Spines 150
Harpy, Heavy Venom Cannon 140
Hive Crone: This guy has been a very controversial unit since he came out... his damage output is potentially brutal, with a strength 8 Vector Strike, 4 Haywire missiles and a Strength 6 flame template. However, he is also a very fragile unit.. He's much better vs vehicles than a Harpy, but a template and Vector Strike could requite getting close. Those haywire missiles make him a great anti-flyer unit however.
Stinger Salvo: Adding an extra gun to a model who already has way more than it can fire feels like a waste of points to me. (3/10)
Cluster Spines: Same as above, the Crone has plenty of guns as it is. (3/10)
Overall: He is a beast with damage output, and can kill a lot of units, but just like the Harpy can get gunned down by a determined opponent. Again, cover hopping is crucial for survival, as well as target saturation. Take multiple, or none, in decent sized games. (7/10)
Example: Hive Crone 155
Spore Mine Cluster: For minimal points, drop three models near your opponent for some fun mind games! At half the cost of before, Spores are no longer random, and instead can move at half-speed anywhere they want. A fun unit to be sure.
Overall: Don't expect anything wild, but an opponent can easily panic and shoot them after they Deep Strike in, and waste a whole units shooting. If you have the points, they're a fun distraction. I wouldn't recommend adding models, as once the unit is targeted, it will die thanks to Toughness 1. (5/10)
Example: 3 Spore Mines 15
Fast Attack Overall: I think that most Tyranid lists will have either an empty Fast Attack slot, or will fill all three. Many of the units here rely on target saturation due to their fragility. However, many of the units have terrific speed and potential damage dealing. Crones in multiples are a terrifying thought for almost every army in the game, and with 9 Raveners added in for flavor will worry even the most seasoned Tau player. Either build a list designed to close with the enemy, or a much tougher list that lacks in speed. But, Fast Attack is a bad place to be caught in the middle of the fence. If you decide to just add one unit in "to fill points" it will be isolated and torn apart. Have a plan for the Fast Attack slot, either to attack en mass or to sit on the shelf. Used properly, and this is a very promising slot.