I have went on rides with several machines, some of which were 4 seaters. They did not get hung up for ground clearance but they did struggle in spots to maneuver in tight spots on trails. They need a bigger area for turning, and tight spots with trees etc.....were a problem at times.
Over all, they did okay.
Obviously there were trails where they struggled with ground clearance in spots, but the bigger issue is maneuvering in the woods.
As far as the Polaris 570. A friend has one in the 2 seat version. It does seem to work well trail riding, and has adequate power for two people. But I would question the power with 4 adults on a 570n ?
I have a couple Rhinos, and I put a seat in the back which we used a few times. Just a back seat out of a jeep wrangler I bought a junk yard. Put it against roll bars with passengers facing back, so I could keep weight centered better.
When we had 4 adults in it, we were always in low range in the woods, and while it never failed to go up a hill, you sure knew you had the extra weight, and they are 700's.
I would say the 570 could haul 4 adults, but I would think it would be shy on power on any hills, especially if you had gear in the back as well. If they wouldn't haul 4 people, they wouldn't sell them as such, just question the power on the hills.
Try looking for any reviews on Polaris, or other atv/utv websites. By the way, the Hondas are under powered, so beware of them. The Polaris machines with bigger engines did a fine job hauling 4 people, and rode with a 4 seat Mule that did good as well, other than previous mentioned fact they are hard to get around tight trails with.