I ride with a couple people that have them one is a 450 rhino and she goes everywhere the 700 Rhino her hubby has. From what I can tell they are pretty tough just don't go to deep(water over bed) as they can get water in their belt, nothing a little snorkle won't fix. I say get one and throw some 27-28" tires on it and have a ball.
just had the opportunity to ride / drive in one this past weekend. what fun it is. I would definitely go with the 660/700 over the 450 as the 450 is a little sluggish. The one i was in had 14" rims and 27" tires with snorkles. What a blast... we were in water up to our necks and it trucked right through it.