I'm not sure about the later batches but mine are probably the most punchy batteries I have used to date, and that's compared to quite a few other high end race packs. I did once have one of the cells in one of the packs go down to less than 2v during a race though.
Luckily I manged to revive it and charge it back up, the iffy cell still takes 7500mah (same as the other 3) when charging, which is a bonus. I have also done quite a few 18-20 minute finals using the batteries since then as well so it appears no lasting damage was done.