Has anyone used these two in combination? Or one or the other? With the Firewire option?

Actually, what would be the big advantage of taking the Firewire option over just the USB?

I am considering a pairing like this as a flexible-ish front-end for a small and hopefully portable DAW.

Is that firewire 800 or 400?

I don't know how much help this will be, because it's a different product, but I'm in love with the Duet and can vouch for it. Beautiful product really.

johnnyshape wrote:Actually, what would be the big advantage of taking the Firewire option over just the USB?

I have never used any gear by Apogee from what I can remember.

Firewire is better suited to streaming data, whereas USB works in a more "bursty" manner - consistent data transfer is not absolutely guaranteed which is what we'd like. So, Firewire is more solid, regardless of whether 400 or 800 speed.

For two channels of audio at 24/96, I would probably be happy using USB as I do this already myself. For say eight tracks and above I think I'd stick with Firewire just to be safer.

Remember the Mini-DAC is just a DAC. 2 channels of digital->analog. It does have a lot of digital input options, if thats what you're looking for. The converters are top notch.
You'd need to pair it with a Mini-ME or Mini-MP is going to run you about $800, so with the Mini-DAC+Firewire you're already talking $1800. You also need some kind of power supply for remote recording.
I've owned an Ensemble since last year. Its REALLY good. I'd recommend that over the Mini stuff. Or go with the Duet, which I think is awesome for field recording. Much cheaper.