@Alex_J : well you're in for a treat once you'll discover the Flatten brush, which is by far the best out of all sculpting apps out there *and* has the option to perfectly conform to the initial normal, producing perfectly flat facets.
For the people having problems with the obj, can you load it yourself outside of the script? If so, you can initialize zbrush yourself, import the obj, then say no when the script asks you to initialize.