I feel certain they will meet your needs and should satisfy you for along time.
A little late for buying advice, but I owned an '02 Kaw Prairie 650. Absolutely loved it and bought the '04 700 next. Same atv, just slightly larger engine. To me, the prairies have to be some of the most versatile ATV's around. Plus the braking system is second to none, and brakes always seem to be problematic on most atv's.
The side-by-side units seem pretty nice, but I have always been worried about riding with my ATV buddies and encountering a low limb crossing the trail. No ducking to keep going oin these. Plus the weight has to be a negative factor when in the mud, especially if you get it stuck!
Grizzlys> I've only been around 2. One was bought used and the man had trouble with it cutting off all day. Probably not a grizzly proplem, just something that could happen to anyone. The other grizzly was new (well, 2 yrs. ago) and when he got stuck and engages 4wd-lock, it broke a front axle. I have heard other grizzly owners say this as well, but with stock tires and no agressive mudding, that should not be a problem.
Polaris- I don't think anybody's sitting on the fence about these. Either thay love them or they hate them. I fall into the latter group based on the ones I have been around.
Ford or Chevy, Honda or Toyota, blada, blada, blaaaah. Everyone has their opinion, but take care of any of them and you should get good service from it.