Replacing 8-yr old Grand Caravan. After months of research, considered and compared Sienna & MPV as two most reliable alternatives. Didn't consider Odyssey - too many transmission failures (although some MPV owners had transmission shift-shock issue; now resolved with updated transmission software flash). I preferred larger size of Sienna; even bigger than Grand Caravan. But price was definitely an issue and wife preferred smaller size, maneuverability, handling, and looks of MPV. For less money, MPV ES also has more standard features than Sienna LE: leather, 6-disc in-dash CD changer, 2 power sliding doors, and alloys. If you have a smaller family and smaller size is OK, then recommend MPV.
Handling is sporty and VERY good for a minivan (tradeoff is that van doesn't ride like a limo). Overall, lots of fun to drive (though engine could use a bit more torque at times). Sharp looking for a minivan too. Nice that sliding door windows roll down. Good bang-for-buck for very reliable minivan.
Mostly little things: Make van tad wider, bigger, more powerful. Add shoulder belt to center rear row. Move shifter to console. Provide control on dash for overhead lights. Allow sliding doors to be locked as they're closing (like Dodge) instead of waiting until they're all the way closed to lock.