Lately I was completely satisfied with 128 kbps MP3s. Now I think 192 kbps MP3 is a minimum.

I rip CDs to 192 kbps AAC files. I wanna save some disk space so I don't use lossless codecs like FLAC or OptimFrog.

The major problems of MusicMp3 for me until now were (sorry, but I have to repeat):
1. I don't trust it yet 'coz it is rather new and I don't wanna lose any money (I use allofmp3 for ages).
2. $20 min transfer.

As for bitrate, it is rather OK especially for portable devices. But it is always good to burn a CD from a lossless codec to listen on a good standalone player.