E.T.
I actually went this week, and we left after 15 minutes because they did not keep the big kids out of the little kid area, there were no other parents in the little kid area even though their toddlers were in there, and a young child spit out a whole bunch of chewed up apple right in front of my son. I had no idea where his mom was, so I had to go tell the workers to come and clean it. Also, the latch on the gate to keep kids in the small area has been broken for about 2 months now, so I really have to block the door, since my son can just push the gate open and wander out.
I have been to this place a few times, and in the beginning, I really liked it. It has quickly gotten where it looks dirty and a bit run down. Also, now that summer is out, it is packed during the day. I will not be going back until school is in session, since that will hopefully keep older kids out of the little area.
That being said, I think your 8 year old will love it, and even your younger child is older than mine, so she is probably sturdier on her feet than my son.