I think he's generally not well liked because he wrote a book and got famous for doing all this ultra running and competing in certain races, but compared to other athletes in the unltra running community, who aren't really famous, he's not that impressive.
Ah beat me to it Shane.
I am a Dean fan though. The author of Born to Run seems to have quite a distaste for Dean because he is so commercial minded, but idolizes Scott Jurek.
You know what though...whatever. I think what Dean does brings a lot more attention to ultra running. I first saw his book in Barnes and Noble and got it because it looked interesting. It is because of that book that I learned things like that were even possible and when I finished all I wanted to do was go out and run. Scott Jurek on the other hand....never heard of him. At least not until Born to Run. Not saying he's not an amazing endurance athlete. Better than Dean for sure. But what's wrong with capitalizing on a talent that you have and bringing some notice to your sport at the same time?