I enjoy mine, mostly because of the Cummins. Like others said, its the only one still available with the older fuel injection pump. The reputation of Cummins was a HUGE factor for me. One other thing was the requirement to remove the entire cab off the Ford if you need engine work on the diesel. That is just one more cost to have to eat.
I moved over from a Tundra. I LOVED that Tundra. I would still have it if my camper and family were light enough for it. That being said, I am very pleased with my Ram.
Like IdaD said though, I think that any of the Big 3 will offer a very high quality truck at this point. Any of the engines and transmissions are great, refined, high power, reasonably fuel efficient combinations. You rally can't go wrong right now with any truck. Find the one that you like the best and your wallet likes the best and don't look back!