Bang for the buck it's hard to beat the RZR 900S. Smaller, yet very capable and can fit everywhere. You did not mention where you would be going or how you will haul it, but there are still a lot of trails out west that limit you to a max width of 50". The new Can-Am Maverick trail is also 50" wide and has a great review/ comparison to the 900rzr.
If you do not need 50" specifically the 900 is also available in a wider version and is still one of the best overall values in the new market. The Ranger is also a great rig, a friend has a 570XP Ranger and it amazes me, even with a bed load of firewood it climbs like a goat. Dont let the motor size fool you. The new 1000XP ranger is insane, and I have generals in the family also, they are really nice.
If you want to go cheap, or want a machine for casual use that wont let you down you may look at the Honda 500 or the 1000.
I have a Honda pioneer 500, it rides a bit rough when stock, has tiny tires on it ..when stock, and has great utility rack on the rear and can fit in the bed of my toad for excursions. You can load the rack with coolers or game etc.. fairly universal.
It is one of the cheapest , smallest UTV's in the marketplace and has Honda behind it. Mine is a bit modified and can really do well riding with the 1000XP RZR's that I ride with in the trails (These Honda's are not a fast machine) I prefer it to many because it does not use a CVT belt and has a manually hand shifted transmission that uses flappy paddles on the steering wheel. Durability is a huge deal to me, I don't want to deal with issues. The newer ones have a dash switch to select automatic mode, I am not a fan of that, used ones can be had pretty cheap. I like the machine overall, and its a great low cost way into the hobby.
Here is a video of a stock P5 at Hells gate in Moab last month. I want to go there with mine some day.
Here is mine, it is a bit modified for black trails.