Keep in mind what you really need your vehicle for. As others have said... in hilly country the hydros are best. But if you are on flatter land and want better performance.... I'd go with something like the Ranger. You really have to fit the machine to your needs.
For my use... rolling country, grassy yard, work and recreation... the Ranger was the perfect fit for me. I like being able to work and putt around.... then put it in High and do 45 mph down the road. Having a higher top speed really opens up more uses for the machine. We went to Eastern KY one weekend... had to haul flowers up to a cemetery on top of a mountain. I was able to drive up the black top highway to the logging road that went to the cemetery. Shifted into low and 4wd... then blasted up the road... it was very narrow and rocky. Worked great! And a lot of fun too.
So it's all on how you are going to use the machine. The RTV 900 is very impressive. You can pull farm wagons, etc with that unit. Very powerful.