1. Child care is much better. They have infant care, and they actually hold your baby if he/she cries.
2. Much better schedule for pool and group classes. You can bring your kids to the pool almost any time during the day because they have two pools. Water quality is much better. YMCA has only 1 hour of family time and very limited time for adults too.
3. They have family changing room, makes more sense if you have multiple kids.
4. They have indoor garage and outdoor parking lot to choose (JCC metro west in NJ).
5. They even provide towels so you don't have to bring your own. When you have a couple of kids, these all add up to the weights you carry.
6. Safety lockers.