My sisters both have Oddeseys, but we just bought a Grand Caravan. It made sense for us because we have never had a car payment in our life! We will likely never buy a new car, either (who wants to lose 40% of the value when you drive it off the lot?) So when we were looking for vans, we budgeted about $8000. The Hondas we could afford for that price were 9 years old with over 100K miles. Or we could buy a 2003 Grand Caravan with 92K miles for $4500. It was a no-brainer.
I did a lot of research on the different models. They said that Mazda MPV's are the smallest ones out there. That's fine if you only have two kids and need some extra room for gear. But if you have more kids, they say skip the MPV.
My friend has a newer Nissan Quest(?) that is really really nice. I would have liked to get one of those instead, but again, our goal was to not have a car payment.
As for reliability, I'm usually a Honda or Toyota girl. But again on the reviews, every type of car has problems. In Grand Caravan's it's the transmission. In Hondas it was a long string of major belts breaking and all the cool extra features not working after a while (like the power-sliding doors). I figured they all add up to a lot of money, so why not start off paying less money for the vehicle?
I dunno, that's the choice we made. We love the room in the Caravan. My kids walk around in there, and I have had so much space to carry the baby gear I'm buying on Craigslist! We got one with two bench seats instead of captain's chairs. I'm not sure it really makes that much of a difference, though. We love all the seating options, so my boys can sit next to each other in front, and we can pile so much stuff in the back, or they can have their own row and have a break from each other. One feature I look forward to is putting the back bench in the center row (and taking out the smaller bench out completely) so the soon-to-be three kids can sit there, and we'll have the entire back open for camping gear, etc.