The non-fpu version is great (mpega & madlib). Quality is acceptable and the speed is great. I always play my mp3z at 22khz because there is'nt much hearable differnce when it plays in the back, but it surely helps when multitasking
Amplifier is very fast too.
For encoding to wav, I suggest the fpu (mpega or madlib) version because this sounds sooo much better (less hiss and mp3 artifacts)