I went through this very issue earlier this year. I don't have a ton of lawn, but it is all difficult with lots of side slopes and tight areas. Total lawn is maybe an acre, if that. I have a friend with an X320 JD (something like that) and he tried mowing it once. It did not go well. He was spinning wheels at various places, and some sections he wouldn't even try. So I knew I would at least need an X500 as they have the diff lock. I went to a couple dealers thinking they would push me into 4wd, and one was doing that but the other 2 both thought an X500 would work for me. I tried one out at the dealer on a severe slope ditch which was not too different from my place, and it seemed solid. I also tried to tip it over sideways when parked on the side hill, and it was rock solid. So I bought one, they delivered and I started to mow. Took me all of 5 minutes to get it stuck, and I had to pull it out with the Kubota. Not what I was expecting. I was in a spot where I had to back up up hill with nowhere else to go, and it would not get traction, even with the diff lock. It was probably the worst spot in the yard. I was able to do the rest of the lawn OK after pulling it out, but I kept thinking about it and went back to the dealer. Here I got a surprise. He said Deere had a 30 day no questions return. Really?!?! Why didn't anyone mention this before? Hmmmm. He was actually pretty apologetic about having to to up to an X738 as they are ungodly expensive, and a bunch more than even the X500. So we swapped. It works. No problems getting stuck and it still has the diff lock in case things get real ugly. I've even started mowing areas that are steep enough i would not have even tried them before. On side slopes, my pucker factor gives out well before the tractor would tip. I didn't like coughing up how much that cost, but I need it to do the job and not get stuck or cause me issues in the long run.
So ask about the 30-day thing so you know where you stand ahead of time.
The one big difference between the X738 and the SCUTs is that the 4wd is supposed to be a special setup to not gouge lawns in turns, and it seems OK for that, whereas a SCUT is going to be full on 4wd, no give at all. It is supposed to back off on driving the inside front wheel or something in a turn. It will still tear up grass a bit turning on steep slopes, especially if it is at all damp. FYI