Perhaps lots of people already know about it, but was visiting some friends over the weekend and we headed to RockCity as we've got 3 under-5's between us as well as being climbers.
Anyway - just a strong 5-star recommendation to that wall. The kids areas are brilliant and huge and ours loved it, even the 2 year old was having a wonderful time for about 3 hours.
The grown-up bouldering was also excellent; varied, well set, nice temps... Kilter board's cool too. It's a huge centre, the only negative I can say is they need to put some signs up to point you towards certain areas.
Maybe it's already known as a great wall locally, but I need to particularly humble as about 4 years ago I wrote a post about RockCity saying it was a bit rubbish and we got turned away for having kids with us. What a difference a few years make.