I'm... somewhat disappointed. People, if you're going to make something to rival the iPod, at least try to match either the sizes being offered (like, up to 60 GB), or include Mac support. 'cause, while I would seriously consider an iPod alternative (iRiver's been something I've been watching, although... I don't know yet.), something I can't use really doesn't work as an iPod replacement.
And replaceable batteries? That issue is long dead, I believe. You're better off hunting for something that can do something brand new, something so utterly awesome, the entire world turns around to look. Maybe an idea expanded upon the digital paper stuff. eInk, I believe it was.