I have the Gens Ace 3S 2200 25C and Nanotech 3S 2200 45C and the Nanotechs are much better. Both weigh the same. Perfect balance with both packs hanging about .5 inch past the front of the battery mount. I hang the heli from Magnet wire tied around the blade grip balls hung from the ceiling
I get 4:30 to 3.7 volts per cell with stock gearing, Gov store and a flat 85% throttle curve. Haven't checked RPM yet, its enough for me though that's for sure!
Batteries are still breaking in too, less than 10 cycles on each of the 7 packs I have.