I'm a Ford fan although I do love the looks of the Ram HD trucks. Anyway, it hasn't been mentioned but it seems to me (I could be wrong) that there is more aftermarket support for the Ram platform. That, and AEV has done an extraordinary job of marketing their upgrade packages to the Ram market, and that increased visibility may have something to do with Ram trucks being viewed as more "adventure ready". Also, until very recently, the Power Wagon was the only HD truck on the market that came from the factory with real offroad chops, i.e. lockers, winch, disconnecting sway bar, small lift, etc. Now that Ford has the Tremor package and GM has the AT4 and whatever Chevy calls their version, there are more options.
Just my 2 cents and I could be totally off base.