I am not too familar with Montessori but many years ago my nephew went to Montessori in Utah and he did quite well.
I just recently (this past week) started my daughter in pre-school. I did extensive research and found a fantastic program at ASU - West Campus. They have a pre-school in their child development center and all the teachers, assistants, volunteers and director etc are involved in early education, education, child psychology etc - it is really a wonderful program and the facility is NAEYC accredited which is one of the toughest accreditations to obtain from the federal government. They really focus on education but it is combined with creative and fun activities that allow the children to think for themselves, logic/reason and explore and develop independence. They are also taught repsonsibility such as taking their snack plates to the garbage, rinsing a cup, picking up after themselves etc - good reinforcment on what I teach her at home.
They also maintain structure and routine which gives the child security and stability. I also have the option to email the teacher anytime during the day and will get a response. There is a computer in the classroom and the child has opportunity to communicate w/parent during the day.
Here is the link www.west.asu.edu/cdc. I know the program still has openings and they offer 5 day a week, 3 day a week and 2 day a week programs. They offer breakfast, morning snack, lunch and afternoon snack. My daughter goes twice a week for 4 hours each day. I pick her up just after lunch.
Also, they keep the classes small. My daughter has 6-7 kids in her class and there are two teachers and two assistants.
Again, I am quite impressed with this program and actually thought their pricing was better than most and they have the accreditations to back up the reputation.
I also like the fact that I can visit anytime I want and I can stay in the classroom for as long as I want. They really encourage parent involvement.
I hope this helps and good luck.