As a few others have pointed out the first point is - what do you need? Where and when will you use it, how to you expect to use it (two occupants or with friends/family, mostly parked, heavy touring).
In our case we boiled it down to a list of must haves (tag axle, 500+hp/1,600 lbs/ft as we drive in the mountains, four slides, king bed, aquahot). Then it came down to what was available and condition/price.
Then drive them. They are ALL sinkholes for money and you can't really tell before you buy, so don't drive your self nuts.
2006 Patriot Thunder