TM, I thing you really do have to know your child. I don't think it works with every kid. I know it would not have worked with my difficult child, but easy child probably would have liked it and excelled.
difficult child did loop in K/1 and that was a wonderful experience! Most of the kids were intimidated about first grade and then we found out just two weeks before school started, that oru school received a looping grant and difficult child's class/teacher was chosen.
difficult child's school has done two multiage rooms at the lower elementary level and it, like the program at Duckie's school, is a parent opt-in program. The classes are always full and we are talking Duckie's age level.
I know you will make the right choice for Duckie.
Sharon