I don't know anything about the duet, so I can't compare, but I do have an Ultralite. I've been very happy with it, but am not currently using it much at all (I used it for my second signal chain when using two MTs for four channels--now I have an R-44 and use two DAV BG1s and a Mytek 192 (digi+analog in for the R-44), so the Ultralite is now only for when I need six channels, which is pretty rare), and have been thinking about selling it. The biggest plus to my particular Ultralite and the main reason I'm not in a hurry to let this go is that it's one of the few Black Lion Audio-modded versions. I had the analog stage upgrade done only (on ALL of the analog inputs, not just the mic inputs), as the clock replacement would have prevented the unit from synching with my Mytek, which was how I always ran it. Anyway, I am very pleased with the improvement from the mod.
There are three issues--two cosmetic and one functional related to the powering, but it wouldn't apply if you're running it with bus power. Eventually I wasn't able to maintain a good seat from either the wall wart or an external battery going into the unit, so I had to tape the plug into place, making it immobile to ensure reliable power. Eventually this took off some of the paint on the top. I then got an AC>Firewire adaptor and it powers the unit perfectly, so when powering from the firewire I'm sure there will be no issue at all. The other cosmetic issue is a slight scratch on the display, but it doesn't affect readability or usability. I can take pics if need be.
So, while I wasn't quite ready to let this go and am still not exactly in a hurry, I might consider it. I have the original box, manual, etc. I think it's a great and extremely versatile piece of gear, and with the Black Lion analog stage mod, it sounds better than it should. I should mention that you're limited to 24 bits at a maximum sample rate of 96k--I think the new version goes up to 192k?
If others want to chime in pro or con about this unit or the apogee, maybe you'll get some more opinions upon which you can make a more objective judgment than I can offer. But if you're interested, I'd be willing to let it go for $425 shipped. If not, that's cool too, as I don't mind hanging on to it for now.