Your question is the perfect launch to start another transmission war. You will be overwhelmed with recommendations to buy what each other member has bought and will be told that his choice is the best.
I had mine rebuilt by James Northrum in Midlothian, TX. James is an authorized vendor and installer for DTT transmission parts and has been rebuilding automatic transmissions for 30 years. He installed all the billet steel parts including billet flex plate, billet input shaft, and lots of small parts as well as a special DTT torque converter in mine. The job was not cheap but I've already put 50,000 miles on it mostly pulling heavy up to 26,000 pounds gross combined weight. It works great, just as promised. I am a satisfied owner.
A fellow transporter, also a TDR member, had an ATS rebuild done on his 2005 Dodge. If you PM me to ask and if it is okay with my friend I'll give you his cell phone number so you can ask him yourself how he likes his ATS transmission. I'll give you a hint, he is not a happy owner.
Harvey