I have 13,000 miles on my 2015i Denali over the course of the past 13 months. No noticeable cabin pressure and/or noise on mine. I did notice it on a 2015 that I test drove before ordering mine. I have had other issues but most are minor and more annoyances rather than deal breakers. To date I have had:
-Exhaust 'chirp' when the butterfly valve in the exhaust system opened (fixed by dealer replacing entire exhaust system under warranty)
-Glitchy flicker in infotainment system. Dealer acknowledges that it exists...GM knows about it, but has no solution yet
-iPhone freaking out infotainment system (switches source over to BT audio whenever I do anything that has sound on my phone)...waiting for a fix from iOS 9.3 next week but in the meantime I have a workaround by just switching Siri off.
-Rearseat video headphones and remote would randomly loose connection to the DVD player and would then just as randomly reconnect. Took it in to the dealer who could not replicate the issue but reflashed to a newer firmware anyhow and it seems to have worked...no issues since July of 2015.
Overall I really like the truck. It is a 3 year lease and I was very concerned about getting a first year car. It is powerful, big enough for me and my family to go on vacation, has a really great audio system and a great ride and feel. There are a few things that I would change on my 2015 (I wish it had intellibeam and to me the windshield washer controls seem backwards...in my brain the front windshield should be on the button on the end of the stalk and the rear washer should be on the paddle half way up the stalk, I also wish that all the power outlets stayed hot when the truck is off). Other than these minor annoyances it has been a pretty good experience. I will seriously consider another one in 23 months.
