The good news: I got to an up close look with the Dell Aero, AT&T's second Android handset and Dell's first in the US. The less good news: AT&T's not letting anyone actually see it work. Hrmm?
Here's what we do know about the interface: it's Android 1.5, like AT&T's other Android phone, the Backflip. That's a bit disappointing, although the Dell rep we spoke to indicated that it would get a proper 2.1 update before long. Other confirmed specs almost made up for it: the Aero's going to ship with a 5MP camera and a 2GB microSD card, and will have a multitouch capacitive screen..
How much of a factor Android 1.5 is going to be depends largely on what kind of custom skin Dell's going to layer over it. According to the rep, it's going to be very similar to the one they currently use in Asia, which looks a little something like this:
As for the form factor, the main thing to know is that it's light. The lightest Android phone, in fact, but it achieves that effect without feeling cheaply made.
It would be nice to know more—price, for one, and on-board storage—but we should be finding those things out sooner than later, as the Aero's expected to ship within the next few months.