Traded in 06 Odyssey and you can't go wrong with either van. But the styles are very different, and we prefer the Sienna. Sienna is quieter and rides much smoother. Sienna also has better turning radius. We took the Sienna on a 1600 mile road trip and loved the journey. And we originally wanted it without AWD, but we ran into a snowstorm and AWD paid for itself in one trip!! Our Sienna is loaded, and it really feels more like a luxury sedan than a minivan.
Quiet interior, aux input for ipod, bluetooth connectivity, AWD, power folding side mirrors, backup camera, adaptive cruise control (feature I did not want until I used it!).
Fuel mileage, Best we could get on our trip (highway) was 18-19 MPG. City is down to 16. Too close to big SUV mileage. And would like more control of the rear DVD from front seat.