I'd go for the X2 for two reasons: The dump box is so handy. If you need to haul something like a flat tire, a couple of 5 gallon buckets with stuff in them or a tool box, the sides of the box will negate needing to strap it down like you do on a plastic platform. You just toss it in the box and go, it's also great for dogs, if you drive carefully.

The X2 is a working beast with touring capabilities, while the other two were built to tour the great outdoors. You will soon find it indespensible around the farm and a very capable two person quad on the trail. I have about 6,000 trouble free miles on mine.

 

This is a 2-1/2 year old thread, but I'm curious, Maxndale: what did you buy and have you been happy with your choice?

I had an 07 Polaris X2 500 (EFI) and make the following observations: drive train was bulletproof, so-so ride, very hard to steer and back seat was uncomfortable, my wife says. Rear truck bed was handy.

We later added an 04 Bombardier Quest Max 650 and about that say: harder to start, much more comfortable back seat, somewhat better ride.

Sold the X2 and recently bought an 09 Outlander Max Ltd. 800R, which is/has: fast as the blazes, very comfortable rear seat, great brakes, great instrumentation, a great exhaust sound, but rather thirsty. It came with a BRP storage box, which is really nice. ALSO, in hot weather tremendous heat on your legs. After researching this problem, I'm going to have exhaust system ceramic coated.

 

I think all 2ups are EFI only. Not that a carb vs EFI is a big deal to me, they both start up and go for a ride I find.
If I was into stretched 2ups I think the new Polaris 570 Touring with EPS would be the bang for the buck camp.