We bought the Odyssey when my second daughter was born. (They are two years apart). I, too, was reluctant to make the move to a mini-van. However, I can now say that the Odyssey is my favorite car ever. Yes, "ever"! Getting the kids into it is a breeze. There is a ton of room for groceries, luggage, diaper bags, etc. I carpool to preschool with another family and there is room for everybody! The in-floor storage helps keep things neat.
Additionally, our neighbors, who opted for a Grand Caravan, have had it in for work at least four times. We have not needed anything done to ours. Of course not. It's a Honda.
My dad has the Sienna. I like his car, too. I don't know anything about the Quest. I don't think you can wrong with either a Honda or a Toyota. The Odyssey is my fifth Honda.
BTW make sure you get the cool rearview mirror! I can't remember if it's standard or an upgrade.
K.