I own an Ace and Rzr's
I would get the Rzr 570
simply because you have more room for gear and can take a passenger when you want to
The Ace is a BLAST to drive, it is more maneuverable, and super comfortable. It will plow just fine, like any ATV but even easier with a steering wheen and one hand to control the winch
The ace uses a different type of suspension from the Rzr, the RZR suspension is far superior in my opinion. However the Ace fills a need for a single seater and they are a ton of fun. This is a tough decision, but if I was in your shoes I would get the rzr
and then go back and get an Ace
Make a list of pros and cons
Ace will be faster, more nimble, more maneuverable
Suspension upgrades and travel are limited, less cargo space (still plenty!)
Rzr, more room, heavier to push MORE snow better, ability to carry passenger /dog/ more gear. Rzr has better suspension
Rzr harder to turn around (slightly), bigger to tow, bigger machine, not as nimble
Tough choice!