I'm torn.

O.O RMVX supports mp3s doesn't it?
In my personal opinion RMXP, is the best, it has the most resources, best scripts and theres many styles of tilesets and charsets. In rmvx you can only use one tileset. >.>

It supports some MP3s, but .OGGs are more compatible.
Anyway, I used RMXP for a bit, and I really didn't like it; as for having the most resources I sincerely doubt it.