Yes, I own one.
I've owned a 12" PowerBook G4, 15" PowerBook G4, 17" PowerBook G4, MacBook (White) MacBook (Black)
And my most recent, a 13" 2009 Revision 2.53GHz. (Although on the 17th it will be a year)
Honestly, this is the best laptop I have EVER owned. It's light, portable, small, has upgradeable RAM and HDD, and is just great for a day of carrying around wherever I need to go. It's also quite speedy.
When I bought it, there were not any i series processors out, so there was no need to worry.
I use Photoshop CS3, and the iLife suite, as well as the older version of Office, and occasionally do day to day gaming. When I'm at home, I plug it into a 23" Apple Cinema Display, and that solves the problem of the low resolution complaints. Plus, after using my second monitor, a 20" Dell that runs at 1440x900, when looking at the MacBook's screen the resolution looks really great! xD
All in all, it's a great unit, however if I was re-buying a computer right now, I would most likeley buy the base 15" model, although I would miss the small form factor and portability of this unit. If I place my 12" PowerBook on top, this model is only slightly bigger. Plus, if you're complaining about the 1200x800 resolution of the MacBook Pro 13" Try using Photoshop or Final Cut on a 12" PowerBook for a month or two (1024x768 :O )
All in all, what i'm trying to say is, unless you plan on doing some serious gaming, or some movie editing in final cut, if you want a great little machine the 13" is probably right for you.When you're on the road and need a unit that has everything (sorry Air fans) a 13" is great. It also fits on most economy Airplane trays quite snugly.