I've used mine as a 2-track in location recording situations, as well as simply replacing an analog mastering machine in the studio. It is great for both purposes.
In my live-to-2 case, I was recording a 2-track mix of a multimic setup for some choral music (~100 voices) in a very nice, very live room. Using the machine in this application is simplicity itself, of course: you just treat it like you would a tape machine. However, there are a few things to remember if you think about using it as a "tape machine replacement" for live or especially for rehearsal.
Most important: with the original v1.x firmware release (which I have), you can't split tunes. You need to punch "stop" to end a soundfile, and punch "record" again to start a new one. This means that the machine needs to be actively operated to split out tunes (to master a redbook CD, reorder tunes, yadda yadda). The editing features can only crop the head or tail of a tune: you cannot grab one take, and split it into two or more tunes. In short: somebody needs to punch a button, once in a while.
If you just want to use it as a high-quality cassette recorder (set and forget), it will do that, of course: but then you're stuck with the whole take as 1 "tune". If your take exceeds the capabilities of a Redbook CD, you're truly stuck with it: you can play it back on the Masterlink, but you can't burn it to CD-ROM to distribute to the band members, or whatnot. The 2.0 firmware is supposed to allow "tune splitting", but I have no experience with it.
For recording a show, you can just take the live feed from the board, of course. For rehearsal, ditto. The unit has no mic pres, so if you are going to set up an independent recording rig, you'll need some pres from somewhere- a little mixer works great for this.
You can obviously take the soundfile, fly it onto a DAW via the digital outs, and then do whatever you want with it: but it sounds like you want the unit to do it all, by itself. It's up to the task, but it needs some operator interaction for best results (with the v1.x firmware, anyway).
Do you intend to burn CD of shows and rehearsals, or is it just going to be used to capture and playback? That's the key, really...