On the new models, yes they are finally adding in a better battery. This is a quote about the sound I saw from IGN’s review of the 40GB Model :
The sound from the MiniDisc was consistently better than the iPod on all fronts, even the WAV file, which is when I knew something was wrong. When a compressed file sounds better than the original WAV file, the difference in sound quality has to be attributed to the unit. This isn’t to say the iPod sounds bad, it just doesn’t sound that good. MiniDisc is known for its great sound quality, but I was disappointed by the iPod’s sound. I understand that I am an audiophile and that the bass problem is one most of you wont have, but overall, the iPod doesn’t sound that good. Distortion was prevalent with almost every EQ, and that was on WAV files, not MP3. Mike has always written that the iPod sounded the worst of all the HDD players, and I can verify it’s true.