I have had great experiences with both Zippy and Turnigy lipos. I run the hardcase packs. As a note, they are not ROAR-approved, but for many people that doesn't matter. Check with tracks and LHS in your area to see if you need ROAR-approved packs.

If you do need ROAR-approved hardcase packs I would look at ProTek (A-main Hobbies in-house brand) they are pretty cheap too, and I wouldn't be surprised if the lipo cells are the same as Zippy and Turnigy.