If you can afford one, buy it.
It's not going to make your skill level increase whatsoever. Not even slightly. To suggest as much is ridiculous. Nothing bought can replace practice and developing solid fundamentals.
I have some nice cues, but most often find myself shooting with a $90 J&J sneaky Pete, that for whatever reason seems to hit just like some very high end cues. I'll spare names to avoid insulting anyone.
It's a distasteful notion, but very true.
If you want a carbon shaft because it's tough and durable, then it's definitely a good idea.
I agree.
I've played with $100 cues that play ever bit as well as "any" cue ever made.
Deflection? Well, thats another story.
Jeff