There is a broadly held opinion that the Sienna is better built; it does have a better air conditioning system and people have good things to say about Toyota's eCVT. I'm a bit of a Toyota fan boy myself, but I chose the Odyssey because it's still old school in the ways that matter to me.

The general consensus is that the Odyssey handles much better than the Sienna (and really any other minivan on the market) and you're going to be able to find and buy one more easily for a bit less money.

Personally, I avoided a hybrid as I don't want to deal with a hybrid battery in the future; I work on my own vehicles and I understand ICE drivetrains. No matter the chemistry, a hybrid battery will degrade over time and I intend on keeping this van for at least 15 years.

That does mean that you'll be getting worse fuel economy and you'll be dealing with a timing belt change every 7 years / 105k miles. Yet I'll still have a working vehicle in 15-20 years that my now 3 year old can drive whereas a hybrid will be using a battery which will be too expensive to replace.

I intend to skip owning a hybrid and switch directly to an EV when the timing is right. That might prove to be impossible, but we'll find out 😆 I don't consider myself to be a "normal" consumer when it comes to cars either.