Had a 2011 Sienna limited FWD. Traded for 2014 Odyssey with high expectations due to better safety ratings, blind spot and lane departure warning, and so claimed better MPG up to 28 MPG on hwy. After having owned and driven both cars, realized each has plus and minus features. If you use navigation often, this would not be ideal car (see below). Cargo area a bit smaller than Sienna, though 3rd row more spacious.
Safety rating, tail light, two separate large monitors. Drives like a car, quieter than Sienna, though could be b/c it's newer car. 2nd row center seat quite comfortable, and can be removed to create passageway to 3rd row.
Lousy MPG. Surface street 14 to 15 mpg (similar to Sienna), and hwy (after 4 hr drive to Vegas) 22mpg (worse than Sienna,which can hit 24 to 25mpg). Navigation: unacceptable extremely limited POI (gave direction to Target or Costco several thousands miles away!!), difficult to use control knob n bad not user friendly keyboard layout (not QWERTY). RES only displays movie in 1/3 screen in center (not full screen). Driver seat does not move backward when engine turned off for easier access to car without hitting head!! Seats a bit stiff. Move sliding door control in front row to overhead position, so either mommy/daddy could close them. More storage in 3rd row (treasure box as child calls it)
You are indeed getting lousy mileage, but that is not indicative of the Odysseys.
We get around 16-17 in stop and go in-town traffic, but it was never a surprise to break 30+ highway with 5 passengers on hilly (live in WV) interstate in both our 2011 and 2014 Ody Touring Elite.
6 mo average in both was 24.7 mpg.
RSE system shows video in full screen aspect, but screen is WIDER than 16:9, so if you are only watching one input, you will have "sidebars".
I've had overhead slider controls (Chrysler t&c), no preference.
I'm one of those "driver controls whats going on" people anyway.
I agree with you on the nav system, it takes some getting used to, and you sure don't want to be entering destinations while driving.
The display is fantastic...love the "countdown" to turn feature.
We test drove the Sienna in both 2011 and in 2013 before purchasing our Odys...as I'm sure that most folks that are looking for this level mini van due.
We felt that the Ody was more than a cut above quality-wise on both models.
I can't drive a Mercedes right now with four children, but the Ody Touring elite is more comfortable to drive and better appointed than the 300SE's that I used to drive.