Urban Montessori Charter School

I am looking for more recent reviews of Urban Montessori Charter School in Oakland.  We have just learned that our daughter is on the waitlist for kindergarten next year.  She has also secured a spot in a hills OUSD school where my other children have gone.  We are interested in UMCS, as our daughter is currently doing TK at a Montessori preschool and enjoys the long, focused work periods and the Montessori structure.  I understand there have been some growing pains, but that now perhaps there is more stability at UMCS?