Purchased with ~98,000 miles on it, put ~20,000 more on it over two years. In that time, I had no mechanical problems with it at all- the car might as well have been new. It's not the most exciting car to drive- I nicknamed mine the 'boringmobile'. Pros: extremely reliable, good mileage, Cons: suspension feels a little mushy and the handling is only adequate. But it's a sedan, not a sports car, so that's okay. Unfortunately, the car was totaled in a collision with a Chevy Tahoe. The Toyota engineering team does good work, I was not injured (nor was anyone in the Tahoe). I start looking for another Avalon this weekend.
Reliability, mileage, amenities, roomy interior (I'm 6-6, and fit comfortably), spacious trunk.