I've heard of those transmission problems a few times, but if that's really the case, how come the Odyssey is still widely considered the best minivan money can buy? Wouldn't those transmission problems have caused the Odyssey's reputation to be somewhat affected?
Besides, sit in the Odyssey and the Grand Caravan back to back... you'll see where that extra $10-12k went immediately.
If I had to chose between the Odyssey and the Sienna, I'd probably pick the Sienna because of its long history of reliability, plus I know a few people that have had them over the years and they've always loved them. But if I'm on a budget and really only need something for 4-5 years before looking for something else, I'm looking for a great deal at Chrysler, no questions.