I was actually just about to buy the Ultra when a local guy put a Depth up for sale for the same price as the Ultra in oak shipped. I haven't doubted my purchase once yet, although I'd still like to hear an Ultra. It's a smallish room, so more output isn't an issue at all, and the sound is all I could need. The design is great too, just to have something that isn't a box.
I think the main difference in performance between the Depth and Descent is output/power, going from specs - the Descent only goes 2 hz deeper, just has more amplifier...