I bought this minivan in 2001. Our first choice was a Honda Odyssey, but in that year Hondas were so in demand we'd have to order one and wait. The Toyota Sienna has been a decent alternative. We have traveled across the country with it and it has never broken down. It has issues, however. Among them are the engine light and low tire inflation light constantly going on and annoying little repairs (struts, CV joints, shocks, and assorted other annoyances) such that I generally have to sink $2000 every two years into the thing to keep it going. Most recent repair bill in April '08 was just under $2000. Brakes seem to need to be replaced often.
Performance, acceleration, comfort, versatility with seating, and fuel economy.
Do something about those dummy lights! Very annoying. I heard about Toyota reliability, and while it's not as bad as our former Pontiac minivan, I'm disappointed with the number and cost of repairs. Over $5,000 in repairs the last 3 years. Kinda expensive if you ask me.