I would echo prior post suggesting that you ask if your son can spend a day (or half day) at the Montessori and the gifted schools. We have found that this is a really good initial screen for our DS. In one case, we found that he loved it and didn't want to leave; while the second one was "boring" and clearly they hadn't made any attempts to help him connect with them that day (despite what they'd told us -- a huge red flag).