This is a very nice set.
Features:
Mechanisms on the back so the arms can move up and down for lightsaber action!
Thumbs can grab!
Head tilts!
Helmet and cape makes it look real!

Pros:
All the features
Stickers
Tall
Lightsaber sorta looks like it's lighting up

Cons:
None

This set is definitely visually impressive. Admittedly, is has limited jointing and therefore isn't very playable, but that is more them made up for by its sheer presence. It looks amazing, and if you want to get a TECHNIC Star Wars set I would definitely recommend this one over 8007 or 8009, the other two from this theme I have experience with.

Box/Instructions

Box has a nice image from the end of The Empire Strikes Back, and the instructions are the usual LEGO high quality.

Parts

Vader mainly consists of a bunch of normal TECHNIC parts, but does have a few nice exclusives, such as his helmet and simply enormous cape.

Completed Model

Summary

Excellent display model, but don't get it if you actually want to play with it.

Although it was rather expensive and I dont even collect Technic,I just couldnt resist buying it.
It looks really awesome once built,and is a pretty good likeness(a lot better than Jango,the droids or the stormtrooper) probably due to the cape.
Someone mentioned the red eyes as a problem,but Star Wars nerds will be aware that Vader had red eyes in the first Star Wars movie:Episode 4 A New Hope. If you like Vader and you like LEGO(who doesnt) Id recommend getting it,but only if you like both. Oh yeah,I guess his arms do fall off pretty easily,but dont let that put you off!

This set was pretty cool except the whole red evil glowin eyes thing , it makes him look way to evil. besides that that set is pretty good it goes together fairly easly, and the helmate part is cool, same with the cape.

Buy it if: you like vader, want all the technic stuff
Dont buy if: u hate vader, ur u want to get somting more playable, (you better not hate vader cause he rules)