2005 Chevrolet Suburban 2500 LS 4WD 4dr SUV (6.0L 8cyl 4A)
We bought the vehicle to tow our 8000lb camper. It tows the vehicle very well, however, it has died on us three times. Each time, we're headed up I-70 west of Denver in 95 degree heat towing the camper. The fuel system vapor locks. Chevrolet keeps replacing the fuel pump, but the fuel pump obviously isn't the problem -- the vehicle is completely drivable (until placed in the aforementioned conditions). If it happens one more time (and we fully expect it will), the state of Colorado will officially consider it a lemon and hopefully we'll get our money back.
Power extending mirrors for towing.
Reliability. It's hazardous to be driving a vehicle this big while towing an 8000lb trailer and have it totally die with no power brakes and no power steering in heavy interstate traffic.