I put the 315 MT/Rs on a couple of months ago. I was so disappointed with the stock Michelins on the ride home from the dealelrship that I immediately started researching tires. I have Super Swampers on my Sami and had 265 MT/Rs on my last truck so I had those experiences to help.
My goal was to get the biggest tire that wouldn't require a lift or new wheels. From the posts here it was clear that 315s fit well, but had a slight rub at full lock. May claim to have solved that with a 2" lift up front. After looking at my trucks front end, it was obvious that the lift is not what fixed the rub. I would suspect that the lift also moved the axle laterally.
Super Swampers don't have very good road manners, but are killer off-road. Since my Ram will see much time on pavement, I decided to not go with the Super Swampers. While BFG, Procomp, and other have Mud tires with good reputations, I knew how the Goodyears are. I really didn't want to spend this much money on an experiment, so I went with the Goodyear MT/Rs.
My experience with the MT/Rs is that they clear mud very well. I don't do a lot of mudding, and what mudding I have done has not been in the gooey stuff. The MT/Rs work well in the snow. But, I don't do much driving in the snow, so maybe they just work well in the kind I have driven in.
The MT/Rs work very well off-road. Almost as good as the Super Swampers. They have very good road manners. I can hardly hear the difference in road noise over the stock. But they are much quieter than the Super Swampers.
As far as fitting, the height of the tires isn't the real problem. The control arm rub can be solved by moving the tires out. They do rub the back of the wheel wheel at full stuff, but a lift alone won't solve that, the bump stop will need to be moved.
Since I am not doing any hardcore wheeling with my Ram (that's what the Sami is for), I am not very concerned about any of the rubbing.
My opinion is that the MT/Rs are the best compromise tires there are. Most of the tire reviews and comparisons I've read in the wheeling mags say the same thing. The BFG mud tires seem to be catching up though.