The 500EXC was my first bike, I really enjoyed Limerick and Calabogie but the bike shines on wider, faster trails. I also took it to the motocross track and ran a few fmsq races with it, I really enjoyed it.
Even if the bike isn't that heavy on paper it did feel like a brick compared to lighter 2-strokes. Still, at 6'1" 260lbs (at the time) my rider to bike weight ratio meant it wasn't too bad for me.
The problem in my case was the power. Too much of it combined with no experience meant that I spent a lot of energy fighting against the bike.
For a city commuter it might be fun but I originally bought the bike thinking I'd ride it to the trails and after buying the bike, my next purchase was a trailer. I really hated the highway, plus my agressive tires melted in no time.
I do have a few videos at Limerick and Calabogie with my 500 on youtube:
http://youtube.com/lcrx121 , just remember that I am a novice rider!