I've held an HTC Diamond and played with it, in GSM form.
My initial reaction was that it was nice, but not amazing as I had hoped. Could be because it was a demo unit, but I'm wondering how the CDMA model will compare, what with all the rumors of various flavors being released on a multitude of CDMA carriers states-side.
Well, thankfully I won't have to wait too much longer- or rather, at least now I have a better idea how much longer I'll need to wait thanks to some supposed leaked internal Sprint documents.
As always, take these with a grain of salt, but it seems to be on par with many of the current release date rumors for Sprint.
More on this over at wmpoweruser.