Once you know what to "feel" for from the buffeting issue, you'll see it is in a lot of these GM SUVs
Every single one I've driven (now over 15 between 15s and 16s) has the buffeting booming to a varying degree
Now to OPs point, much fewer had a vibration issue, in my drives about half of them
BS
If you have to be told to "feel" for an issue, you don't have it.
I don't doubt that there are a VERY FEW that have a legit issue on the buffeting, but the majority of this simply comes from people who are not use to driving big vehicles with large sealed interior spaces.
I have a 2015 Tahoe LTZ (Sunroof, 22's, towing, etc) and I don't have any issues except that the ride is more stiff than I would like over some surfaces.
Way to many people with "imagined" symptoms and people looking for an excuse to dump their trucks.
I would encourage you to take the truck on a long test drive WITHOUT the salesperson and without the radio on. Take someone else with you and see if they have any sort of reaction to the pressure changes if they do actually exist.