Do whatever floats your boat. I was a Ford guy since I was old enough to drive (I'm 61 now) and made the switch to Ram 2 years ago. No regrets at all. I looked for deals on GM trucks but nothing around here at all. GM sells 1/2 of what Ram does in the diesel versions and Ford sells 2x+ as many SD diesels as Ram does. Makes it hard to get a good deal when GM's are far and few where I live. Can't hardly find a used Dmax that's only a couple years old.
IMO all 3 make great trucks. Each has it's quirks but in the end it's just a matter of personal taste. Not every butt is the same so the one that fits right is the one to get.