I have the MS70D and absolutely love it -it goes just about everywhere with me. Converting the MP3’s to ATRAC is a pain admittedly, but worth it once you realise how good the sound quality is and how much more it will allow you to fit on the device. At 64kbps ATRAC, and using an extra 128mb memory stick, I have about 16 CD’s on my player at once. Sure, an iPod carries a lot more than that, but realistically how many CD’s do you really listen to at once?! :D
There’s also an MS90D now which I think is only out in Japan, but has 512mb built in memory. It’s also black instead of silver in colour, but I prefer the ‘bare’ titanium look of the 70D.
Get one - you won’t regret it.