This sounds like a tough choice, MON. I guess I would also factor in cost of the private school as a "but"...maybe distance from home, convenience, etc.
I am a big advocate of an arts curriculum, so missing specials to me would be a big deal. My DD and DD are in private school, and I'm grateful that they don't have to take state testing, so that's a plus in my mind for the private school.
I guess I'm feeling conflicted about your decision, too - partly because I've been going through a decision process again for my kids. Each alternative situation has a "but" - something we would lose by going there, but gaining something else. Maybe get your DD's input on it?? Sorry I'm not much help...
