Almost 5K miles in 6 months.
First problem was CDs only played in the DVD player - were ejecting from the CD player. Dealership tried to reprogram - no dice. Had to order new stereo - took three weeks!!! Replaced and everything works fine.
Then, about a month ago, got Service Rear Park Assist after driving thru some large puddles after huge downpour - OnStar, GM rep via OnStar and service advisor at the dealership weren't sure was was wrong and suggested give it another day to see if it goes away, which it did.
Last week, was going to lunch and trans light came on dash when I started it up. Called OnStar, ran diagnostics and don't remember exact message - something to do with emission system malfunction. Went to dealer, they cleaned it, light went out and ordered new emmision vent valve or something and went back next day to install new one.
When I first got it (Feb'07) was rather cold (Chicago area) and had squeaky brakes first thing in morning or when first driving at lunch or after work. Went away within a few minutes. Seem to be a regular thing - I have heard "Large truck, brakes will make noise"; condensation problems, normal on these models until you break them in. With the warmer weather haven't noticed it anymore. On the next oil change (only using Mobil 1 5W30) will have tires rotated and brakes checked.
Other than that, I have no complaints. A lot of people say the Bose stereo sucks but coming from a '97 Tahoe LT, this is big step up. Only get 14mpg but most of my driving is city. Few times I have made some road trips noticed my mpg going up. Gas finally coming down - $2.89/gal - Chicago highest prices in the nation. Was $2.28 when I bought it and was as high as $3.89/gal. Whew!
Sorry so long - that's about it - got few updates - got Benevento sunroof deflector, Weathertech floor mats and window vent visors, white Lund bug deflector, chrome bowtie for front and back and OEM cargo mat (took 3rd row seat out 1st week after I got it!) Wash it at least once a week - white is tough to keep clean but looks damn good when clean!