The exclusive version, which comes with a mouse droid, has been sold out for a while now. That one is limited to 2000 pieces. I'm not sure what the edition size on the regular version is, but AFX has it for $350.
The non exclusive is 2000 as well. And to answer your question yes it is absolutly worth it. It's the best representation of Vader that I have seen so far. On that note the Grievous looks even better and new Predator maquette is absolutly MIND BLOWING in person. It was the best piece Sideshow had on display at the Con this year.