I'm using an Archive Python 25601, firmware is v2.75, and controlling it with vDAT, (v2.0.0). A three hour DAT will take 3 hours, this particular model only supports 1x transfers. I've read that other DDS drives can go as fast as 3 or 5x, but I got a pretty decent deal on this drive. Either way, it saves the head on my main deck, and the software is pretty much set and forget. You can tell it to record either between IDs, or from a set Atime > Atime. It writes straight to your drive as WAV, and is completely bit for bit perfect.
I've never transfered a tape through a soundcard, so I don't know how much better it is, but it is certainly damn easy!