I dunno, I've played with my Mom's Moment, and can't stand the feel of the thing. I cannot use the hardware keyboard (neither can she), nor can I use the Moment's on screen keyboard. Stock, the Hero was pretty darn good, with the slight issue from the standard messaging app (now fixed--notice the quickness of the maintenance release from HTC compared to Samsung). That faster processor on the Moment doesn't seem to help the phone much when I compare it to my Hero. In fact, the Moment just looks so plain stock compared to the Hero(the only true out-of-the-box comparison). When you start digging into rooting the phone and really messing with things, the Hero still outshines the Moment.
Granted, to each their own when it comes to preference, but I far prefer the size of the Hero compared to the insane bulk of the Moment (not to mention the loose slider mechanism--perhaps an issue with my Mom's phone?).
Overall, I'd say go play with the things. don't make a decision based on what people on these forums say, make your own decision based on personal preference.