i have a 2014 blue Viking with EPS and I trail ride and work the crap out of mine. I have 28" tires on it and can still run 50 MPH and it doesn't care about the tires. I runs great up hills and across them as well. I Haven't found anything I cant use it for. Recently I have used it as a tractor, my dad is clearing some land to build a house and I have been using it to pull logs and root balls with, I have pulled a bunch of logs 10' long and 10" in diameter with no trouble and I have pulled a few Ceder root balls that are 3' across the ball with 2' of the tree standing out of it and I wasn't lacking any power. In fact my dad stood back laughing as I brought one of the root balls up over a bank to the brush pile, he said it looked like a "bantam rooster coming up over the hill". I was spinning all the way up the hill, so there was no lack of power and unlike the Polaris's I have had there was no belt slip either.
This past summer I loaded my wife and my 3 daughters up and we went to WV to ride the Hatfield McCoy trails. I built a roll cage for the bed and installed a rumble seat in the bed so I could safely haul my daughters. we covered over 130 miles and everyone was comfortable. In-fact my youngest daughter was in a booster seat I had strapped in the middle seat up front and she ended up sleeping a good bit while we where out riding. I thought it was a very comfortable ride and even with a booster seat installed it didn't feel cramped up front.
As far as the heating issue goes. I haven't had the issues out of mine that it seems everyone else has had, and like I said above I have used the crap out of mine and I have never seen the exhaust turn red.
I love mine and I would Highly recommend one to anyone looking for a good sxs to work with and play with. I have had a blast with mine and its even a blast to work with. best of luck to you and I am sure you will enjoy trying the Viking out this weekend.