I saw on the mailing that you a Felix have been doing a great deal of work to provide better support for the M-Audio FastTrack Ultra. I tested yesterday the new patch that provides mixer and the possibility to change the internal routing of the soundcard... I can finally use all the input/output to use external FX, that's very handy!
Anyway, on the M-Audio forum, Felix has been mentionning several times that there were few bugs that needed to be fixed with this soundcard, but that you needed to get your hand on one device to fix them (and may be even improve things around its support in general).
Quite frankly, I'm not fully aware about known issues with these devices that need attention. Could you summarize which problems are left to look at?
There are still the issue of samples dropping.
Tto reproduce it: - Open Audacity and set it up to be using Jack. - Click Generate -> Tone -> Ok.
"Normally" you should hear very regular pops...