I've played around with it briefly, but never used it for a couple of reasons. The main advantage of mp3PRO is that it uses a smaller file size than a normal mp3, and non-mp3PRO software/hardware can still read a lower bitrate version of it. I thought that it would be useful, but in the end I realized that most of my hardware doesn't support it, it wasn't worth re-ripping my entire catalog, and I didn't see a need to pay for the encoder (it isn't free like the mp3 codec). The only advantage it offered was more storage space, but once I went over 12,000 files, saving a few MB or GB here and there wasn't really worth the effort, especially since hard drive prices keep falling.