I did a private cooking event last year with a guy who used to sell them and now runs his BBQ joint completely off the things. His BBQ is good and he knows what he is doing. But if I wanted to do BBQ, I'd rather have an offset or a WSM or something similar.
They work fine for BBQ, but they aren't cheap. Keep in mind I prefer gas for the convenience during the week for quick things like steaks, burgers, and chops. If you want charcoal all the time, the Hasty Bake is pretty versatile and can let you do it all.
Edit: It was
Burn Co Barbeque for anyone interested. He rarely does private events but my boss had a hookup.