If you're looking at one I can tell you that they sound great and play well with Sonar. A few things to know about the unit:
1. It works great via USB, but only if you keep the cable pretty short, so if you have a machine room or closet where you computer is you'll want to keep the unit in there.
2. There aren't any pre-amps included, so if that's what you're looking for it's probably the wrong unit. Also the analog I/O is all D-sub so you'll likely want a patchbay.
3. the routing is a bit limited. I run mine alongside an Aurora 16 via MADI from an RME HDSPe MADI fx so it's not a problem for me, but if you use the onboard mixer for cue mixes or whatever your options will be limited.
Beyond that, it's a great unit and does work well...been pretty happy with mine.
Good luck
Dean