My (generalized) take:
The pro world and the audiophile world are worlds apart without much overlapping. Neither generally have much respect for the other side, almost like Democrats vs. Republicans. The pro guys tend to be suspicious of cables and tubes and efforts to make recordings sound 'pleasant.' Audiophiles veer away from any harsh sounds and like exotic parts and tweaks. I think we can both learn a bit from each other.
I'm redoing my (amateur) studio set-up with a new Macbook Pro and some ADAM speakers, using Logic Pro. I'm attracted to using the Apogee Duet -- it's a lot of technology and sound for the price, and firewire is a good-sounding way to get audio out of the computer. But then I have a North Star DAC and a BV Audio preamp that I'm not using, which probably sound better than what's in the Apogee (at least they should, for the price difference). Of course, then I'll have to use a Toslink out of the computer, or get a USB-coax coverter, like the offramp you mentioned. Right now, I'm leaning toward using the Toslink and getting a jitter box (the Big Ben is probably great, but too expensive) to go before the DAC.
I plan to borrow a friend's Duet next month and I'll compare. I'll post my findings.