I hope this response isn't too late, I don't check this board as often as some of the others
We have a 2006 Niagara and love it. I can't think of any cons at all.
The pros for us include, the hardwall bathroom- privacy and no nasty campground showers, The built in microwave-one less thing to move off the floor, the direct sewer hookup (I guess that goes with the bathroom), the cable hookup outside-better then running the cable through the canvas, furnace, bigger box, light switch-you don't have to turn each light on and off on the ceiling.
There is probably lots more but I can't think of any right now. The radio is probably a plus for some but I have never taken the time the learn how to use it. Same with the oven, but I look forward to learning how to use that!