I've been running one on a Mac for 3 years now. It's been great. In the beginning I was just thrilled by 8 ins to my mac via Firewire--though I never really used all of 'em at the time!
Now, it's still the "hub of connectivity" in my studio, with 8 more preamp channels coming through it via ADAT, and external pre's in 6 of the 8 Tascam channels--for a total of 16. (BTW-- the Tascam pres are fine--should definitely be better than your Behringer).
Don't know if you do MIDI, but the midi connections are great too. I use those as well.
If you end up getting it, PM me if you need any help with it. Like I said, I've been using mine to death for quite a while. (Oh yeah--I paid $600 for mine!)