I'm staying in Childs Hall at the moment so methinks I'm qualified to give you a little insight!
I applied for the same reason as most; it's sold as being very community-orientated, social and 'the best Hall to stay in in your first year'.. and I'd have to agree.
Childs is without doubt a GREAT laugh - I've had loads of fun here, and all the corridors/units are really big so if you don't get on with the people directly around you, you don't have to go far to find others!
Dining room's big and eating together's a very big plus for first years, as it gives you opportunity to talk to loads of new people etc.. probably goes without saying, but there you are.
One thing I will say, though, is that Childs is the very definition of 'basic'. When I first arrived here I was quite shocked!! The building's very 60s, and it kind of shows - corridors are all green floors n white walls, funky! But the rooms are a very good size and the furniture etc is in good condition.. most rooms have sinks (mine doesn't!) but none are en-suite. Bathrooms aren't amazing but they're clean [usually!!] which I guess is what counts.
Basically, it's not the most stunning of halls and probably won't win any awards for aesthetics!! But with regards to fun and 'having a laugh' etc, it's definitely the best hall.
I've gotta say the spirit, atmosphere and general community in the hall more than compensates for the average-ness of the hall itself.
Hope that helps, anything else you want to know, PM me!