termagant

I've played WH40K years ago with a Grey Knights army. I'm now coming back into the game, and I'm starting with the army I've wanted to since I first discovered WH40k. I'd like feedback on this first 500 points of my Tyranid army. Any constructive critisism is welcome and encouraged. =HQ=...

In a 1000 point game, how should I use a Tervigon? Should I camp it on objectives and continually spawn termagants, or should I move it forward with the Termagants it spawns, making use of the Brood Progenitor special rule?