I'll throw in that I do ROTJ paint ups in addition to my helmet kits, but any of the other makers are also fantastic. It may be economical with shipping costs to have the maker and painter of the helmet be the same person (which I do both) but if you're not planning to have it painted by someone else then that's a different story, obviously.
Definitely check out the threads that are already out there, and also what's currently available in the cargo hold, especially this thread:
New to TDH? Read this about how much you will spend!
Beyond that, I'll be more than happy to answer any of your ROTJ questions personally!