Pretty good. We went for this as an alternative to a full-on mixing desk for our mini-studio. Eight separate XLR/TRS inputs, plus all the optical expansion capability you could want. Outputs (main L&R, phone L&R, and optical) are fully configureable in the monitoring software.
AudioDesk is bundled with it - which seems to be a fully functional piece of audio sequencing software. Not particularly pretty, but got all the features we needed so far. Will probably use GarageBand and maybe Logic in the future with our Youth Project, just for simplicity's sake.
Only snag is that it HAS to be plugged into a computer to work as an audio interface. Without detecting a firewire connection to a computer that has the software installed, it simple functions as an optical expansion device - and I couldn't get a peep out of the phones or monitors.
Easy once we knew how - but feels a bit odd that you can't switch over manually.