I have AT4 Ultimate Duramax...if I had to-do over, I'd have gotten a Denali Reserve and saved the money.
The biggest reason for this is the build quality. The truck is built on the same line with the same mediocre craftsmanship and parts. You're not getting more attention to detail, more insulation, better programmed damping, better programmed electronics, better fit and finish like you'd get in a Cadillac. It's a GMC, built just like an LT Tahoe. If they truly treated an Ultimate like vehicle the commands another $10-15k, then maybe.
The massage seats are not powerful enough to be noticable.
The leather isn't any more softer or more plush.
The extra speakers don't add anything noticable.
The rear seat entertainment is trash without a Roku or Fire Stick.
Heck on the AT4, you don't even get a special/different set of wheels or an Ultimate fender badge.
And at the end of the day, it has the same issues and service bulletins as the as an Escalade, Denali, or a Z71. Fit, finish, and quality just suck for these $100 vehicles. If the $15k gave you better trim, fit, finish, quality, aligned door panels, better fished paint, longer warranty, then maybe.
I do love how my AT4 looks. And with a family of 6 + 2 dogs, there is not other vehicle in the market that accommodates us. So while the size and usability of the vehicle is great, I could have saved $15k and accomplished the same thing in a Denali. Just my opinion from a financial stand point.
I will say that my AT4 Ultimate Duramax XL with the Brembo Brakes, Night Vision, and Illuminated GMC logo MSRP'd for $108, and I paid $98k which was $107 out the door including enclosed transport to my state. So I saved some money.
I just wish GM would try harder.
