We're near Joe's Movement Emporium and I toured before signing my kid up for dance classes - their afterschool program was going on at the time and I was so impressed. Those kids are having exposure to such a fantastic ranch of dance and movement forms, homework help. It just looked like a blast, so enriching, and there's no way I could find that range of cultural offerings for that age group in a weekend class.
Onsite afterschool activities can also be fun, with your friends, but it's usually just some homework time in the library, playing on the playground, etc. It's fine, but it's kind of just babysitting, whereas the program at Joe's was an actual enrichment program and really it's own curriculum of impressive offerings, IMO.