I like Castboolits and feel that for aspiring boolit casters there is no better place to gain knowledge in that area. Some of the guys there are truly awesome in their knowledge of the subject. I've spent many, many hours reading posts there over the past several weeks and have greatly expanded my knowledge of cast boolits in my time there. Castpics is a good reference site, just haven't had time to explore it thoroughly. I reloaded over 25 years before I cast my first boolit. Some reloaders have no interest in cast boolits so will likely never venture to either site. Sad, but I've come to accept that. It's not for everyone.
THR is very similar to here, just don't see the point of reading two similar forums. I'd have to give up shooting or reloading to hang out there.
As far as an all around loading forum I think Shootest is right but that may just be because I like it here.