Honestly, I've had great luck with the 2 cell Turnigy packs but out of the three 4s 4500mah hardcase packs I bought I've had 2 of them die on me after 2 or 3 runs each. Everything would seem fine but when I went to charge them they showed up as 3 cells on my charger. That's the only 2 batteries that I've ever had to go bad on me. Maybe I just got a bad batch, who knows. I'm going to try out the Gens Ace 4s packs now and see how they do though.