I'm not going to be a whole lot of help, since we just have one year of school under our belts. But I'm sending you good vibes and know that whatever you decide, you're making the best decision you can for now, and things can always change.
In response to your subject line, we have had extremely good luck with the teacher this year, as Kindergarten really isn't the right level for DS6 in most things. But the teacher has done in-class differentiation, and DS6 has also been lucky to have pullouts and daily accelerated math. If we didn't have a gifted program, I think I'd still go for teacher fit over grade level. But I'm just speculating - it's hard to think of such a big jump! Good luck!
