In reply to Rhi Rhi:
Whilst it's fashionable to knock Horseshoe, I don't think it's as bad as people make out. Bolts are generably in good condition - many have been replaced either by the BMC or Gary Gibson.
Rock stability varies, the right hand side of the slabs is fine, but more care is needed on the left and particularly the newly excavated routes in the centre. Plus, identifying and climbing friable rock is an important skill to develop. Just make sure you wear a helmet, especially for belaying
Mind you, with the weather the way it is in Sheffield at the moment, I'd be making plans to visit one of the walls !