There's nothing wrong with asking the question, but I'm not sure why you'd entrust such a personal and subjective decision to people on an internet forum.
If it were me, after weighing all the factors (which it seems like you've already done), I would just go with whichever school feels right to you. You say you "don't have an instinct", but certainly you're closer to the situation than any of us...you must feel something. (And I'm not sure what to think about you saying your wife's instinct "has a bad record." Nobody can predict the future, and I don't think you should necessarily write off her feelings just because she may have made a decision or two in the past that turned out poorly.)
I mean, there's no "right answer" here. I'm sure each school has its pros and cons, and besides, at the end of the day, the type of experience your son has is going to depend on numerous factors, many of which are completely beyond your control (such as other kids in the class, etc.).
All you can do is make the decision as best you can, and stay supportive of your child and family throughout it all. (And if it turns out to be a bad/incompatible environment for your son, which hopefully it won't, you can cross that bridge when you come to it.)