My daughter is 15 months and really enjoys Kindamusik. I think it is important to identify which development stage your child is at (are they walking, do they like music, or do they just like socialising). My daughter used to love Gymboree and we thought she gained a lot out of it, but I think since becoming much more active, has lost interest in it. In Kindamusik our particular teacher is quite laid back and not bothered if our girl doesn't want to sit still whilst doing the group activities. I would also recommend not only getting recommendations on different activities, but the teachers can also make a big difference too. I would recommend asking to do a trial for any of the classes you choose.
Best of luck!