Like many have reported, the front wheel bearings both had to be replaced. GM had issued a bulletin stating that the Rendezvous had inferior wheel bearings, and would replace them as long as the vehicle was under 60,000 miles. On mine, BOTH became problematic at 62,000 miles. Dealer would not lift a finger, had to replace them myself.
The rear end became really noisy at about 80,000 miles. Read on the Internet that this was also a common problem. Dealer wanted $1500 to fix it. I found out that the "fix" was to simply change the rear differential oil and drive it for about 300-400 miles - the groaning sound went away. The VersaTrack fluid that they recommend is like $80 per PINT, and it takes 8 pints to refill. Talked to my mechanic friend and I replaced it with a different gear oil for $12 a quart. Problem resolved for $25 and 30 minutes of my time vs. the $1500 the dealer quoted.
Rear tailgate strap has broken 3 times - $60 per replacement. Left it off after the 3rd time - they don't even last a year intact.
Speedometer started intermittently not functioning at about 70,000 miles. Problem became more frequent, had to replace the instrument cluster - $500.
My garage door spring broke, door came down on the third brake light and broke it. Dealer wants $450 for the simple little LED light bar... smoking crack they are - I took it completely off.
The rear hatch pressure pad became corroded and ceased working at about 50,000 miles. Was able to fix myself by rewiring to the 3rd unused contact in the switch. Dealer wanted $250 for the 3 square inch rubber button...
Have replaced the rear wiper arm 5 times at least - spring sucks, and it fails to wipe the window. $80 each.
Gas mileage far below what is stated.
The AC / Heater blower motor is anemic - it's highest speed pushes far less air than my Expedition on low...