Not an 800 Can Am...but I have a buddy with a 1000 Renegade and it's been getting fixed as much as he's ridden it. Busted the rear diff yesterday for the second time, not to mention 3 or 4 broken axles. Granted, they have 82 hp stock, but to me it's uncomfortable and the lack of a front locker really sucks. I two wheel most places on a Grizzly 700 where the 1000 or 800 is in 4wd slinging mess everywhere...even with my 29.5s vs. their 31s. I'm very satified with my Grizzly and I've been a Yamaha fan since I got my first one...a Bear Tracker lol..then a 400 Big Bear and now a 700 Grizzly FI non-EPS. BTW, the Grizzly has a very good power to weight ratio compared to some of the other big bores.
A guy at work is getting rid of an 800 Can Am, not because he doesn't like it, he just wants a side by side. Otherwise he is a big fan.
It's up to you though. Since it's an even trade (as long as both are paid for), you can't really go wrong either way. FWIW, I rode with a friend of a friend earlier this year who had a 660 Grizzly with 23,000 miles on it. No motor work, original belt, but obviously regular up keep. Haven't seen anything else with miles on it like that.
Wouldn't have a Brute Force if you gave it to me. Just not a fan...seen a lot of them tore up, but more than that I just don't care for the looks of them. To each their own.