I read a report on 2000 mah class batteries recently, the ones from Hextronic (I don't know if that's what United Hobbies sells for sure but I possibly) came out consitantly in the 10 and 15C tests on the bottom. They had the lowest per cell voltage and the highest heat gain. At 15C they were the lowest voltage and the test was terminated prior to the end due to the temperature getting too high (cells would puff if they got too hot, up near 170 to 180 degrees). They didn't even test them at 20C. Other cells brands were in the middle of the pack, and the two top of the pack brands were ThunderPower and maybe Polyquest or Evo or Vampower in the middle.

I've ran three different generations of cells on the Mega 22/20/2 setup and puffed cells several times from flying too long, that was with the 8000mah 4P packs. With these 5000 packs I can't fly as long, but they don't get as hot (less resistance in the bigger cells) and the power is higher than the old cells. You may save some money buying the cheaper cells but I can't tell you how they'll run as I've not tested them, but if they're built from the smaller hextronic cells I wouldn't waste my money. EDFs demand a lot from batteries, high amp draws to match the performance of prop airplanes. The 5S 5000 Thunder Power extreme pack is about 275 bucks I think, that's cheaper than the old 8000 5S4P packs, which were 400 bucks (and I couldn't use the full capacity anyway due to heat buildup). You could buy a 150 dollar pack and have to watch the throttle the whole time because you're worried about heat and maybe it will last but if you puff it you end up having to buy the good pack anyway. Buy cheap, buy twice. I have a hard time throttling back with a jet.