Have you ever had one of these larger utility quads without PS to compare it to? I have yet to
drive one with PS and would like to try it. I have a little time on the Polaris 850 Twin, and a
few hours on a KingQuad 700. Both were large, heavy, and very softly suspended.
My neighbor has a Grizzly 660. Same size and weight, looks almost the same, but an older design without power steering. His is just more tiring to ride and harder to maneuver in tight sandy areas or in rocks. He mentions being tired after rides, but I'm not. I think it's like having a much lighter machine. It still takes some effort, but it's easier. If I shut it off and turn the bars back and forth, it takes about twice the effort.
I also use the Grizzly to move a 2,000 lb flatbed trailer around the place and maneuver it into tight spots. Lots of steering at slow speeds. Easy. When riding fast I'm more relaxed because the bars are much less likely to get jerked out of my hands. And the Grizzly will really haul if you want it to. I ride between 5,000 ft and 9,500 ft all the time, a lot of it in sand and some of it steep, sometimes with my wife on the back and it always has enough power, or it will idle around all you want and never miss a beat.
I wanted a quad for a long time. When I finally got one I opted for the 700 Raptor. What a hot rod! Explosive power and a live rear axle with 2WD, manual tranny with reverse. Way fun and lots of sliding, but I realized I should have gotten the Grizzly to have the racks, the 4WD with locking differentials, low range, long range comfort and a tractor-like workhorse. So I went back and got it. Now I can roost around and steer with the throttle on the Raptor, or I can load up a bunch of gear on the Grizzly and venture up into the mountains, or tow a trailer around the place. When someone comes to visit we have two machines to go exploring with and fortunately, I can leave right from my place on the machines and ride as far as the tanks will allow.
I've put a lot of miles on dirt bikes, but the quads suit me much better now. There are a lot of good machines so just pick one that seems right for you. You'll keep finding more and more uses for it. The 550 is also a fine machine. I've seen them after years of serious abuse or lots and lots of miles, and they still ran just fine.