So on my DX50 with fw 1.22, I just got a different battery in, its KINPS branded, didnt know what to expect, but there is a definite difference in sound from stock battery, bass has increased immensely, more slam, more sub bass, treble has been tamed slightly, sound stage is smaller, everything sounds closer to you, vocals and instruments are all forward without being harsh, over all I prefer this sound. The stock battery sounds more balanced overall, but the treble is extremely tizzy for me and the bass is too soft, although the stock battery sounds a bit more transparent, and wider which I really like. Now I definitely want to try out a samsung battery, as the change in SQ from battery change is quite significant to me.
I get the impression that there is a lot more power behind the KINPS battery. But from the stock battery I get the impression that the power is cleaner. I'm hoping a samsung battery will combine both these traits :)