Jambo park was a lifesaver for us this summer. Our almost 3 yr old loves this place and we found it to be a fairly clean and safe environment for her to play while it was too hot to be outside. Not crowded at all during the weekdays and the staff has always been very nice and helpful (and we've been there a lot). They may not have all the rides running at the same time when it's not busy, but there are always several options and it's not a bad thing to practice some patience, so no complaints. I can't speak to the Mesa facility, having never been there, but the north Phoenix one is a good time for the preschool set.