Help with a battery choice... Neu XP 25c or the Hyperion g3 vx 35c... BUT

Curious to you guys running the Neu packs, when you charged them at 5C did you notice a drop in performance? I have the Neu 5S XP 5500 and a Zippy 5S 5000 that are both 25C. When I got the Zippy, I also got the Icharger 208B. I was still charging the packs both at 1C and they ran very similar. When I started charging the Neu at 20 amps, it doesn't seem to have the punch or top speed of what it was. Just asking you guys if you were seeing the same results. Not trying to start a good/bad discussion on Zippys since people are so opinionated as it is.