fireberd
Two channels vs four for the Quad unit.
Yes this.
It's only really a concern though if you need the 2 digital inputs and outputs.
The preamps are the same and I'm pretty sure everything else is aside from the digital I/O.
Autosens is only a concern if you have difficulty turning an input level knob.
One thing I do like about the quad though is that it has an internal Main Mix out channel which it's possible to loop back into the input channel. I use that quite a bit so that would be a major minus for me if that wasn't implemented on the Duo although that probably wouldn't be concern for most. Also bear in mind the sample rates available are only 44.1 and 48 kHz also.
Fuller specs are here now.
http://www.roland.co.uk/p....aspx?p=1248&c=665 Looking at the prices that dealers have got up so far for initial launch though there doesn't look to be enough of a cost saving over the Quad for it to be worthwhile. I'm sure they will drop after release though.