My children went to a party today and it was much nicer than other jumpy places in the area. The jumpers are taller than ones you see at the park and they are clean. There is adequate supervision by Pump It Up staff members, though you stay with the kids and you sign a liability waiver when you get there. There are two rooms and you start in one and then after a while the kids are taken to the other. Parents are allowed to go on the inflatables and I did and it was quite fun. There is hand sanitizer prominently placed on the walls and the staff went out of the way to make sure the kids were clean before moving into the party room for refreshments.
The only drawback is that it was far for me coming from Foster City. I have heard they are coming to Belmont soon.