Well according to what was said, MP3 Pro files can play on any MP3 player, but unless it's MP3 Pro compatible, you will loose the quality benefits of MP3 Pro. I don't think an encoder is out yet though, so you might as well pick your current favorite and go with it.

I use Audiograbber togther with Lame 3.87 set to VBR 1. Seems to work fine, and with the newest Audiograbber, it supports ID3 V2.