Outflanking Genestealers with Deepstriking Trygon, Doom, and Zoanthropes, all supported by Reserved Harpies, Biovores, and Hive Guard for long range support. Top it off with the Swarmlord in Reserves (Alien Cunning works at the tournament I played at).
If you go second. Don't deploy unless the opponent also didn't deploy, then you rush across the table with everything and sack him when he enters piece meal.
If you go first, don't deploy.
You want to go second preferably.
Your opponent will scurry around for two turns castling up in the center, where the biovores, doom, mycetics with cluster spines, hive guard, and Harpies will converge (most of the time all at once) and lay waste, giving your Trygon and Swarmlord time to position himself to kill off the toughest units. You will have denied your opponent 1 turn of shooting in a six turn game, and if you went second you denied him 2 turns of shooting (even better!).
Sounds pretty weak huh?
Except that the entire time your 5 minimized Broodlord led genestealer squads are seizing objectives or massacreing anyone that didn't castle up in the center.
This list also trounces Space Marine Drop Pod Assault and Deathwing Assault for obvious reasons. It also gives you the Alpha Strike against a Alpha Strike Imperial Guard Army.
The best counter I have seen is a master of the fleet in a leaf blower with a Inquisitor with Mystics.
Last edited by SHarrington; 05-18-10 at 12:42 AM.