I do not own one, but I did play with one a bit.
The size was a little off-putting for me. The 4.3" screen is wonderful, but to me it's just too big to be a device I drop in my pocket when I'm out and about.
I also wasn't a fan of Motorola's UI they put on top of it. Easily changeable with something like LauncherPro or ADW, but the stock interface feels messy and disjointed. Wasn't a big fan. Again, it's easy to change that, though.
Overall, if you don't mind the size and UI, it's a good phone. I wouldn't own one, but that's more of a personal preference. Just make sure you try one before you buy it.