Olive Mary Stitt is an excellent school. Arlington Heights District 25 is a top-notch school district (you can't go wrong with any of the schools in the District) and I'd say Olive is one of the best. From what I hear, this is one of the most sought after schools among new teachers and administrators. We moved to the Olive area a couple of years ago after attending another school in Arlington Heights (Westgate) which was also very good.
I grew up in Arlington Heights and attended a Catholic school here. I am amazed at how many more resources the public schools have here than the private ones do. When I say resources I mean, excellent staff most of which are tenured teachers, a friendly and progressive principal and assistant principal, a wonderful library with newer computer equipment, programs designed to encourage teamwork among classmates and even across age groups, an active PTA and sense of volunteerism among parents. If your child has any special issues, there are dedicated staff resources at the school to handle speech, Occupational therapy, remedial reading, gifted programs, shyness issues, etc. I never thought any of my children would require the use of any special staff resources but my son ended up being selected for reading help. He went from reading at the median for all 2nd graders to the 74th percentile-in just 5 months. I cannot say enough about how great Olive is.
If you do end up in Olive, you will be assigned a mentor family who can answer any questions about the school for you. We took advantage of this program when we moved here, and now we're a mentor family for this year's new arrivals. Hope to see you next year!