It's hardly a deal breaker but since I do tend to marathon through some titles on my days off, it can get dicey. For the PSP, the real killer is multiplayer. That drains the crap out of the thing which gets annoying when you're doing versus mode on Dissidia or multiplayer in the Arena in Birth by Sleep. My other issue with the battery on the PSP is that it seems to recharge more slowly than the DS, and I know more people where the PSP battery got old and won't recharge if you are still playing while plugged in. Despite the inconvenience, the PSP still always had the better sleep mode and is much kinder to you when the battery runs out. Unlike the DS where I had some races with the devil to get it back home to my charger before the battery dies and I lost my data.

Since I do tnd to "sit down and play" my handhelds as opposed to the typical 2minute micro gameplay that most people seem to use, battery life can be important to me but really, I remember the Game Gear and Gameboy (and even the Lynx if you can imagine that) so getting more than three hours of battery life is just awesome in my book.