I hear good things about blackbear for gm and 5 star for fords. No idea who tunes dodge/ram.
There is only so much a tuner can do for a gas engine, most of the seat of that pants feel comes from turning down the effect of the torque management. When I step on the gas of my non tuned truck it feels really sluggish most of the time. It isn't that the truck doesn't have the power is it that the computer chooses not to let me have it. The power increase usually comes from changing the tune to a premium gas tune. A tuner is probably worth maybe 15 peak horsepower on a stock truck and maybe 7 horsepower of most of the curve. You can get more out of it if you have changed other things that weren't retuned to optimize your changes.
A diesel has a lot more that the tuner can change to effect performance. Often it is at the expense of emissions.