We towed our 26' 7,000lb trailer with our 2008 Yukon XL Denali with the 6.2/6sp. It was capable, but was at the tongue weight limit. We packed carefully but still were near the limits. Towed great (my opinion at that time), except in windy weather where it was at times where the experience was less than desirable.
We traded the XL Denali in on 2011 2500HD crew cab. Night and day difference, towing experience was greatly improved.
Some of the things working against you on on the SUVs,
soft suspension (luxury ride)
P metric tires
tongue weight limits
hitch flex (hitch is part of bumper crush zone and has some flex)
near payload limit when loaded
Advantages of 2500 truck
LT load range E tires (yes you can put them on SUV, but the ride quality will suffer)
higher payload
stronger hitch
At the end of the day, it is your choice, but we went with the truck. Now understand that we ended up with two vehicles, truck for pulling trailer and hauling things, SUV for wife. We don't put alot of miles on the truck (on purpose). We started with a GMC Terrain for wife's car, but did not like it as much as we had hoped, replaced it with Tahoe.
Once we got the truck, we also started looking for a slightly bigger trailer with slide (which we found). The XL Denali would not handle the current trailer (bigger, heavier, etc) where the truck handles it fine.
