That's not really fair. Up above, you praised iRiver, Creative, and Rio as being more flexible than iPod. While the Creative battery replacement looks fairly simple (which may influence my next DAP purchase), the iRiver's instructions from the same site are far more complicated than the iPod's: use a special screwdriver to disassemble the case, break the glue that holds the battery in place, disconnect and remove the hard drive, then completely remove the motherboard from the case, all just to access the battery's plug! (Suddenly I'm not all that keen on keeping my h140 forever, no matter how good Rockbox turns out to be. When the battery dies, I'll make sure the player gets a decent burial.) And Rio doesn't seem to have a battery replacement option at all.
I was talking about the firmware in terms of flexibility. yeah, creative's the only one with a decent battery. I'll probably go with Rio next. They are made by the same company that makes Denon stereos. I always thought Denon made the best stereos so I figure they'll pay attention to the way the rio sounds, which is the whole point after all.