I see you already decided on MPT.
As others have said, they are probably the number 1 choice on this forum due to their Engine and Trans tuning. I asked them for smooth shifting in Normal mode when I ordered mine and it does not have any of the harshness others have reported. It holds the shifts when I want it to and shifts smoothly until I use Sport Mode.
I had 5-star on my Gen 1 and I was pleased with their tuning on the 6.2L truck. They had a lot of issues with their Gen 2 tunes in the early days, so I did not even consider them when I bought mine. Things may have gotten better, but I never saw a need to change from MPT.