I do believe through EXO-6 this really is the only way and only time to get high-end 1:6 Star Trek figures in this era. Even if some other company happens to grab the license in five to ten years from now, they'll only hit up the principal characters from TOS and even fewer from TNG. That's it. Forget about any of the other Star Trek shows and films.
Like most, my interest lies in firmly with TOS and somewhat with TNG. The TNG line promises to be quite tempting, though, and as it comes together it will be hard to avoid the completist impulse that demands building a collection of the full crew. The Beverly Crusher sculpt tease had me sold already, and she's a low priority character. Beyond TOS and TNG I think ST:TWOK is going to be impressive - Nanjin has promised (and practically threatened!) how important that line is to him - so I'll likely cave in to most of those figures. How can anyone not want a killer "Kha-a-a-an!!!" figure?
While I avoided Voyager and DS9 (actually wish I could have jumped into the DS9 figures, but some priorities and sacrifices had to be made) I did buy Seven because it was a unique and interesting EXO-6 project, which turned out rather nice. I may make the same exception for T'Pol, but I really don't like the cartoonish head sculpt much. T'Pol will be one of those purchases that "is what it is", because we'll never see a better T'Pol ever again.