None of the non-sculpting tools were useful to me either, like retopology, map baking, UV unwrapping and poly-painting. Not to mention the need to adjust to the 100% different UI and controls between them. I personally have a far easier time SubD modeling the base mesh, at which point I can also more easily just sculpt out the high poly details in the same modeling program anyway, much more easily than porting it back and forth with GoZ while handling multiple versions of meshes. I just recently re-sold my copy, because I wasn't satisfied with the use I was getting out of it.
Starting out, you won't get good use out of ZBrush, and you don't know yet if you'll even get good use out of it later.
I got ZBrush first, and it was a huge mistake.