I loved my Sienna. We bought it when it was a couple years old - drove it until July 09 when it was totaled in an accident (not my fault). It had only 147,000 miles on it and we were planning on keeping it for at least another 50,000. I can't say I walked away (standing on the brake gave me a knee injury), but the airbags did their job and other than the knee, I am fine. The only negative maintenance experience we had were the plastic door handles that did not like the desert heat in El Paso, TX. We were replacing them one at a time as they gave out. I was not fond of the location of the radio (too low on the dash), but other than that then layout and comfort were excellent!
Comfort - good ride, easy to get in and out of (even had friend in their 80's who used third row seats), roomy interior.
Newer Toyotas have moved the radio to an easier to read and reach position - great improvement! Wish they had had fold flat third row seating when this was made - glad it is now available.