I guess I will chip in. I have had Ford, GM, and Dodge (and Nissan) vehicles, and of them all, I am probably most happy with the Ram I have now. Is it perfect? No. Does it meet my needs, and do I enjoy driving it? Resounding yes!
The new Hemi in the Rams is rated at 390 hp, 407 ft-lbs torque, well above the GM 5.3 or Ford 5.0. The transmission is a 5 speed, compared to the others 6 speeds, but I find it to be very good. It doesn't downshift nearly as much as the GM 6 speeds I have driven, and it also doesn't stumble like they do either (like when accelerating and you have to lift off for a second, then get back into it). The Hemi does have cylinder deactivation (MDS) which cuts it from 8 to 4, similar to the GM system, but I haven't heard of any issues with the MDS like I have with the 5.3. I am averaging right around 17 mpg in mixed driving with mine (40% rural hwy-65 mph, 40% interstate-82 mph, 20% city-stop and go). This is with 3.92 gears and 33.5" MT tires as well, so his mileage would probably be better with a stock size/tread tire. The ride in the Ram is VERY good, much better than the Fords or GM's I have driven, but there is a slight trade-off with the Ram's coil rear springs in that if he hauls heavy loads alot, the rear does probably sag a little more than the leaf springs in Ford/GM. I have had some fairly heavy loads in the bed of mine (don't know exact weight, but the bed was heaped full of damp wood mulch) and it dropped about 4". I haven't had any problems with mine, but I only have about 9k miles on it so far. From what I have garnered from the Ram forums I am on, some do have problems, just like any other brand. Some of the common things mentioned are: a slight tranny shudder when accelerating, some folks talk about a "surge" when the MDS kicks in or out, some have rust spots on their chrome bumpers, and some with leveling kits which increase the CV angles talk about a vibration under hard acceleration in 4wd on hard surfaces(user error if you ask me). I haven't had any of these issues with mine, so hopefully it will stay that way.
Whichever he decides, I really don't think he can go wrong with either Ford or Dodge, and as mentioned before, I would put dealership service high on the list as a deciding factor. Good luck!