I am looking to get a new atv. But I am not sure if I want to go with a 400 class or a 500 (maybe even 600 & up). What are the advantages and disadvantages of both. I just want a good all around machine. All around as in, relaiblity, speed, work (utility), ride, handling, mud, 4x4, hills...etc.

Some models I am considering are: the Honda Rincon, Honda Rancher 400AT GPScape when it gets here, HOnda rubicon, Yamaha kodiak 450, maybe grizzly, Suzuki Vinson, AC 500i, 400i, and Polaris SP 500 HO.

 

I would seriously consider the 2003 vinson. I like the fact that you can get it ion a 5 speed modle, and it has power upgrades from 2002. switchable 2/4 wheel drive, reliable, decent $$$, quick, and it think it goes over 60mph. for a 500, I think it is a nice machine, has a decent ride, and handels good. and it comes in red. that would be my pick over the others. reasons:

rincon: still new, unproven. $$$$$$$$$$$$$$$$ at least for a while.
400rancher: can't coment on it, but I doubt it is any faster than a vinson. still has 5.9" of suspension.
rubicon: doesn't have it hit of a 5-speed tranny, of the power of the vinson. more $$$ than the vinson. Now, I realize the hondas are an extremly well engenered machine, and you may not want the best power.(there all close anyway) I'm a honda man, but I like the vinson a bit better.
I'll cover the A.C and polaris now. Too heavy. not as sporty. More of a cruiser, smooth trail machine.
kodiak 450-again the vinson probably has more power and cooler looks. but it is cheaper. nice speedo on the 450.
Grizz-more power but more $$$, and not a standard. You may want an auto though. I just love shifting. I would take a Vinson over a kaw, honda 650 because of the snappier throttle response, and gear choice. Of the 650's were a 5 or 6 speed though, I think my opinion/choice would change.

 

Yes Cats are heavy but they are not strictly smooth trail machines. Not only do they offer the same engine and trannies of the Suzuki quads but they also have IRS (ACT or IRS on the 400), more ground clearance, and disc brakes on all models. However at this time you can not get a locker for a Cat (due to their different front diff) while you can for a Vinson and hop up parts are fairly limited.
I've been doing a little (my girlfriend would say a lot) of thinking as to what my next quad will be. The best rule of thumb I can give is to buy the biggest ATV you can at the time. Search all the different forums, test ride and create a pro/con list. There are no bad wheelers out on the market but there are some that shine more than others. Just because on person prefers Hondas it doesn't mean you can't like Yamahas.
The Vinson, Sportsman line, Cat 500, Traxter/Quest, would be the models I'd look at (all personal preference no scientific reasoning). One more thing to consider is the availability of aftermarket performance parts; it's always nice to have several options instead of one or none.