I just bought HL last week. It is great for creating characters and NPCs. I have never seen better. You can advance monsters by level and add templates. It is all in the demo. If that is what you are looking for, you should buy it now.
It is powerful for creating your own content, but doing so is non-trivial. I am trying to port a 3.5 template to Pathfinder. I thought it would take 20 minutes. I now realize it will take a couple weeks for me to come up to speed with a proprietary scripting language with no roots in any language I am familiar with. For the record, those languages are: C, C++, Java, C#, Perl, Ruby, PostScript, and shell scripting in UNIX and LINUX. I am not saying it is bad, I am saying it is non-trivial.
Because the editor is complex, it is also powerful. From what I have read, there isn't much you can't do with it.