Wow, I'm so surprised these GM vehicles have so many problems. My wife has a 2014 Toyota Sequoia that we bought new in 2014. It has only 40,000 miles but still after all these years we have had ZERO issues. And I mean nothing, at all. I just assumed that GM had "caught up" in quality especially with their $80,000 SUVs.
I personally LOVE the way the Yukon XL Denali (and Suburban too) looks, that massive GMC grill, the LED lights, the sound of that Denali engine. I've been planning on buying one for a while, however, like someone else said, I think the 2018 Ford Expedition may have leap frogged the GM vehicles for 2018. Expy has better technology: full stop/start semi-autonomous cruise, 360 surround vision (I still can't believe GM doesn't offer this in Suburban/Yukon XL at $80k- especially when they offer it in the Acadia! also the Escalade), more USB ports, rear screens that can play independently from each other, can stream movies from your phone or stream TO your phone/tablet..).
I also like the extra leg room in the 3rd row on the new Expy, and the panoramic sunroof-wow.
The other safety item I like about the Expy (and Sequoia) over the GM vehicles, is that Expy and Sequoia have head rests for all passengers, including middle seats in the 2nd and 3rd rows. Headrests are important for all passengers. And probably even more importantly the Expy gets better crash scores and rollover avoidance scores than Suburban/Yukon XL.
On the other hand, here's what I like (LOVE) about the GM vehicles: the history. You can't beat that history, longest running name plate in history. Also man those GM vehicles look great! Inside and out they really cannot be beat. Also I like it that you can order different versions of the 22 inch wheels. Love them all, and they change the look dramatically. With Expy Platinum you are stuck with one wheel. I still can't believe that.
Also, I haven't yet heard the 18 Expy, but the GM V-8's sound great.
I also really like the fact that GM sells a ton more of theee vehicles than Ford does. That says something. The market speaks with dollars and other people really like Suburban/Yukon XL.
Who knows what I'll end up buying. Even with that exhaustive list above, I'm still leaning somewhat towards the Yukon XL Denali, because it looks fantastic. But I will wait to see the 18 Expy in the flesh.
But after reading about all these problems with the Denali, I'm getting a little worried. I also agree that when you drop $80k on a car, the AC should not go out...let alone all the other problems people mentioned. I do wonder if some of these problems have been resolved by GM since it's been a few model years since they changed everything in 2015? But even so, I bought a BMW in 2011 during a model change and NOTHING has broken, ever!