Our older daughter has taken ballet class at Adagio for several years.
We did summer classes one year. It was similar to the school year classes, but instead of having one teacher, the teachers rotate every other week or so. Otherwise the format was the same as the school year. Our class was even smaller in the summer than during the school year, so there was plenty of attention from the teachers. At 6, they still do a story and dress up, but the class has transitioned away from the games they start with at 2-3. I agree with the others. The summer is so short, that you can always switch in the fall.
While I think the owner acts at times as if Adagio is training the next dance phenoms and takes herself too seriously, the reality is that the classes are fun and that's what the girls get out of it. The staff is pretty responsive. I'm not trying to get my daughter to be a professional dancer. My daughter simply loves to dance, and this has been the perfect outlet for her. She has learned quite a lot and has loved her teachers.