The Hero is an amazing little thing.
I got it 2 weeks ago in exchange of an iPhone 3GS that sorely disappointed me.
I own also a Nokia N97 and and HTC TouchHD (which is 10 months old but still the best win mob phone money can buy,at least here in Denmark where Toshiba's TG01 is not available), but the Hero has quickly become my favorite phone in a very short time.
If you liked the MyTouch (which was'nt bad) you're gonna totally love the Hero which is much much, much better in every aspect: speed, UI, camera, screen, everything; and that's why HTC released it such a short time after the identically specced (on paper) MyTouch.
Try to read the thread about the new ROM (2.0) due out in a couple of days and you'll be even more tempted to upgrade from myTouch to Hero.
The only thing I really don't get is why the American (sprint) edition has to be so much uglier than our squared chin european version; sorry about that guys, but in any case go for it.
Ive had it for over 2 weeks and it still surprise me every time I use it.