Be wary of the Creative Zen Micro and it's claims of 10-12 hours of battery life. It has been discovered that the micros have a power hungry 'standby' mode that remains on for 24 hours after each shut down. Depending upon your listening habits you can expect as little as 4 hours total play time (as is the case with my recently purchased micro). Sure, 10-12 hours can be acheived with continuous playback, but you will not get close to that if you turn it off for hours in between listening. Creative seems to be unresponsive about addressing the issue too. Their latest firmware upgrade (1.02.05) does not help the issue, even though Creative claims it fixes the problem. See the links below for the full details.
I never felt there were significant problems with the Zen Micro. I really have to come up with a complaint, it’d be the sub-par headphones that are included in the package. It’s a small problem, though, if you intend to buy separate, better quality headphones anyway.