What sort of dance studio are you looking for? Ballet/jazz/tap, or something else?
This is a partner dance forum (ballroom, swing, argentine tango, etc). Do you want to get your child into partner dancing or some other type?
(Also, where is Vaughan? Which state, country, etc?)
Generally though, regardless of the type of dance - go visit studios yourself, talk to the teachers, find out about their backgrounds and teaching philosophy, talk to some other parents, get information on prices, etc. See for yourself if the various available places seem like a good fit for your kids. Don't make a commitment to the first place you see without doing some checking around.
In general, when looking for a dance studio, it's not about which is the best as much as which is the best for you. The question really comes down to what you're looking for in a studio before anyone can answer that question for you.