I've had my Passport for over 4 years and it has always been as good to me as I have been to it. I bought it with 86K on it and have only had to make repairs typical of it's age. No major engine or transmission problems yet at over 120K. Compared to other SUVs of its age and class level, I'd say it is average to good. Things to watch for are alternators (tend to start 'chirping' or 'squealing'), power steering pumps (can start to hum loudly), and be mindful of CV joints because if they wear out from maintenance neglect they're expensive to fix on this vehicle. Overall I would describe this vehicle as rugged, reliable, and durable. The mileage to power ratio is terrible though.
The 4W drive, while not shift on the fly, is excellent. I live in Northern Minnesota and have driven it through actual blizzards many times without ever getting stuck once. I've even been called on to pull out arguably more capable SUVs, such as a 2002 Dodge Durango.