I know mpc's sound better than mp3's but can anyone sum up all the reasons mpc is better than mp3. Also apart from portable player compatibilty is there anything mp3 is better at than mpc ?

1.WorldWide Acceptance.
2.Loved by commonfolk.
3.Removing more bits of data from audio sources.

MPC has gapless playback.
I actually have my whole cd collection encoded as mp3, but there are a few cds that have numerous tracks that run together that I have a seperate MPC directory for in addition. I prefer MPC but my car stereo and my nomad made the encoding decision for me.

Your friends will all ask you why you accidently named all your .mp3 files .mpc and you will have to guide them to a WA plug-in to enable playback on their computers. But otherwise, nah, not really.

This really isn't an issue if you don't trade music.

It isn't even an issue if you trade music. MPC is better than MP3 because of gapless support, replaygain support, best fidelity among lossy codecs in high bitrate (esp. when mp3's lowpass is taken into consideration), faster encoding/decoding ...