We lucked out with a preschool near a University. Against all odds more than half of the other students were at least MG. At the same time, I caution you that the value of the experience was largely the result of the teachers, and their attitudes.
This was our experience. The university based preschool was a fit on paper, but the teacher was not. In the end, we see our DD thriving with a particular teacher rather than a particular program.
DD is in a modest program with a warm, insightful, seasoned teacher, who took DD into the pre-K program when she was less than 2.5. The pre-K class size is small (6-8), and the teacher has a daily toddler program, so she understood DD's mind and nervous system.
For us, the teacher made all the difference.