I had an older model, it worked decent in mud, or water, but if you had a foot of water, and mud under the foot of water, you didnt move, and just made muddy water. As you can imagine they (at least the older model I owned, steered like a skid loader, so if you were in mud, and you needed to turn, it would stop one side from spinning, and only drive one side, and if you were in a light, soft mud, this then pretty much stopped you in your tracks. Another issue, when I owned it, I lived in MN, the DNR made me license it as a boat, the other issue is MN DNR being so liberal, you cant disturb a wetland, so if there were certain types of vegetation growing where you were riding, you would get a ticket for that as well, even on your own land.
I owned it for about 5 years, and I had gotten 5 tickets from the DNR, and been reported for everything from no watercraft license, driving it in a swamp/pond, driving it on a township road without registration, which at the time, I wasnt able to register it for offroad.
Mine was also a bit under powered, it had a 12hp in it when I bought it, I took that out and installed a 18hp and it would still bog down considerably in water. I realize todays models come with much more HP then they did back then, and laws have changed, but from the few people that I know that still own them, they hardly ride them, because they just are not ideal for anything.