I've got about 8k on mine with a lot of off road on rocky trails around the area here. No flat spots or dents in the rim. I have heard the rims are soft and there are others who have had the same problem, so you're not alone, I'm just not one of them.
I have not heard of anyone with problems with their rear rim though.
If you do get Woody's wheels, he's probably already told you to go narrower.