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I have been using the new codex rules to run some battles. Mostly fighting Plague Marines (gosh darn that toughness). Some quick thoughts.
Winged, pretty well outfitted with every biomorph that makes sense for a H2H only monster. He also gets one set of scything talons and a lash whip/bonesword combo. I also have been taking warp field, because it is the only way to get him down to a 2+ save and he actually gets to make a save against lascannons. I like the way he has been working. Last game, he hide out behind some rocks, just creeping into position, waiting for a Carnifex to get rid of an annihilator that was covering an avenue of approach. Once the tank was gone, the Tyrant was able to chew his way across the battlefield, including joining 4 leaping warriors in an assault on the Plague Marine Lord with retinue. The increased initiative is superb, you can actually kill lots of nasty folks before they start swinging those lightning claws at you. The Tyrant lost two wounds, but his implant attack smeared the opposing lord and, the next turn, he chewed his wa through terminators with ease.
I have been conserving points, only taking the BS upgrade, adrenal (to be faster than a powerfist, if need be), extended carapace, and the upgrade that gives you 5 wounds. No regeneration and no increased toughness - those start eating up points. For weapons, he has a venom cannon and a barbed strangler. The mix does pretty darn well at hunting tanks and armored vehicles. Plus, when those are gone, he does a good job of hurting tough infantry units. I generally take two carnifexes and, last game, they destroyed one predator on turn 1 and got the other on turn 3. Not bad.
I put a lot of upgrades on these. They end up being pretty darn expensive, but the broods are made to chew into Space Marine squads. The reduced cost for bioplasma is nice and the symbiote rippers make a unit of 5 warriors count as 15 for resolution. Not shabby. With scything talons and rending claws, they give you a whole lot of attacks and chances to get rending hits.
I have been giving them a try. Really, with no upgrade for H2H and just concentrating on shooting upgrades, they are cheap. Buy one two devourers and, thanks to the new rules, the weapons become a single twin-linked devourer. One carries a venom cannon, while the other four are running with the devourers. It makes for a lot of shots, with rerolls for misses and then rerolls for failed wounds. Best against units with low toughness, like Tau, Eldar, etc. However, not bad even against Space Marines.
Give them synapse and warp blast. Spread them out across the field. The synapse not only gives you another node, but it also means that they cannot be splatted by a lascannon. Their warp blast is effective against Marines and heavily armored vehicles.
I take him with a small retinue. Usually, they infiltrate and chill out, just menacing the enemy, until my battle plan can get rolling. Then they come out and go for it. The Brood Lord is mighty good at chopping through squads of Marines, but do not expect him and 5 genestealers to hack through 14 Plague Marines. Still, they can put a good hole in the Marines, but that darn powerfist champion sucks.
The fleet of claw is what I have been asking for, for years. I only upgrade these guys with extended carapace and flesh hooks. It makes them superb at breaking enemy strong points and keeps their cost down.
I do not take them without number. Honestly, their job is to rush forward, forcing the enemy to expend a shooting round to work through 20 wounds (to a brood). That and tying the enemy up in H2H, while genestealers or warriors close the gap.
My list has been looking like this, against Marines (at about 2000 points):
1 Flying Hive Tyrant
1 Brood Lord and 5 genestealer retinue
2 broods of 5 each, Leaping Warriors
1 brood of 5, Shooty Warriors
It makes for a lot of work for the enemy's heavy guns. It is nice, because the Carnis can sit back, in cover that gives them a cover save against the lascannons, and blast away at the heavy weapon threats. Also, with so many synapse creatures running around, nobody is ever out of range.
That looks like a Pretty solid army list, to me. I'm a Death Guard player, (see sig) and I play Tyranids often. The thing is, any clever Death Guard player will give some of his aspiring champions a Plague Sword. This spells death for your big beasties, as its the closest thing to a force weapon in the chaos armoury.
THe broodlord is a good plan. Genestealers work well against them. Gaunts are damned near useless. Its good to tie them up, but with Nurgles rot/true grit, the Spinegaunts won't last long.
Zoanthropes work well, and a Winged Hive Tyrant is a good plan. Just remember, send your Genestealers after and plague sword armed guys, and your big bugs after any Manreaper armed guys, as they'll only get 1 bonus attack against them.
Hope that helps.