So the game we rolled up was a standard Relic mission. We had to play on a 4' table, for lack of a bigger one, but we both had assault armies so it wasn't too bad. I ended up winning by tabling Swanky in turn 4. I also secured First Blood and Slay the Warlord, while keeping my force fairly high-strength.
I learned that Word Bearers can be absolutely beat-stick with the Dark Channeling rules. I also determined that Val Gorbak units are fairly beat-stick as well, and darn survivable for such low-model units. Daemon summoning was also a great boon. The ability to conjure full units of Bloodletters reliably once a turn proved to be a crucial component of my success. Mhara Gal tainted Dreadnoughts are absolutely fearsome as well, as long and you keep them far afield from your own units.
Swanky learned that Regeneration is vastly overcosted... rarely did the larger models make enough wounds back to make the points worth it. Also, she found that psychic powers can be a potent key to the success of the tyranids.
The game ran for something like 5 hours, but it was time well spent. I enjoyed the game, and using 30k Word Bearers for the first time.