Are you referring to the Antonio Carraro tractors or the Carraro tractors? They're actually two different manufacturers, even though they are founders are brothers if I remember the history of those brands correctly.
The Carraro tractors are also specialized tractors but more of a conventional tractor design instead of the isodiametric design of the Antonio Carraro ones. I don't think Carraro is even available in the US though.
As far as the Antonio Carraro tractors, while I've not owned one, there are loads of them working daily about 25 miles South of me. It's a big orchard farm area on some nasty hills and these tractors just fit that type of farm perfectly. Mainly pear and apple orchards, literally everywhere.
What I've noticed is that the people who own these tractors, really don't want to let them go. The rare occasion that a few that pop up for sale, are tractors with over 8,000 hours with just regular maintenance. I think that says a lot of the quality and reliability of the tractors. Not saying that it's a perfect tractor that won't break, things happen obviously, but it's still pretty good.
Not entirely sure on what they offer in the US, but the tractors usually come setup with R1 Radial wider tires, and looks like some extra wide high flotation tires good for wet areas but Turfs are also available. I've seen them with duals as well, mainly on videos over in Austria.
I don't want to sound like a salesmen, but I legit think they make a very good tractor and I keep earing nothing but good things about them. I almost got a AC Tigre 3800 had I spoke with the right people behind the counter on that dealer, but the guy I ended up meeting didn't even bothered to come out and show me the tractor. The price was right at the time and would fit my orchards very well though.