UPDATE: i've been talking to the guy with the cr500 and we're working out a good time to meet, probably going to be sometime next week! i'll keep you guys updated as much as possible!
i've rode one once before but didn't get a whole lot of time in on it. i won't be riding it alot, just enough to get a feel for it and maybe show up some ignorant 4 poke riders haha. i don't hate on 4 strokes, but i know that they can be beaten easily by some smaller 2 strokes.
The modern CRF150 is prolly real close to the power of the old XR.
The XR will outlive the high strung 150 for sure though.
I'm personally not a huge CR500 fan. It's a big bike and a handful to start.