So I got the Melodyne Essential that came with X3 Producer.  When I registered it I got an offer from Celemony to upgrade to Editor for only $149, which is clearly a good price.
 
What advantages does Editor have over Essential?  Why should I upgrade from Essential to Editor?    I know you guys use Melodyne.  What is better about Editor?

I'm in the same boat as you, and got the same offer. From what I've read, Melodyne Editor is polyphonic, and has more pitch/time adjustment capability. I know that after experimenting with Essential, I'm really thinking it's just a preview of what Melodyne can really do. I for one am going to upgrade when I get the extra cash.

Polyphonic would be a big reason, and a great price for it. Unless Essentials fills all your needs then you don't need to but I use the polyphonic feature a lot.
 

Editor lets you work on multiple tracks in one window, great for lining up and balancing harmonies.

Thanks to all of you.  Seems like a great deal and one I should take.

I think it's only good thru the 16th. I thought about it but, I finally think I'll pass on something! My recording studio is just for me and I do things one at a time anyway.

I think the upgrade window is really too short.  Dropped $150 on X3 Producer and I can't justify another $150 by the 16th. 
 
I'll wait for cyber Monday or xmas sale then go Editor 2.
 
There are so many flavors of Melodyne it's all a bit confusing Essential, Assistant, Editor, Studio.  I think I need to keep using Essential for a while before jumping to higher priced.
 
but saying all that - Essential that comes with X3 is pretty damn cool.

I've tried to resist this but I can't for much longer With ARA integration I think it could be one of the best additions Cake have ever made. I agree the offer doesn't run long enough, it's a fairly hefty amount to outlay in 2 weeks with sonar too, but at the same time it really isn't. Now there are AD packs for sale. Will it ever end?? Hopefully not. Just ... Need ... More ... Money ...

Just do it.  Don't hesitate.  Editor brings a whole new tool box for your fixes and creations.  It is awesome.
 
Rimshot
 

Unfortunately I have to wait too. With birthdays and Christmas coming up, I just can't swing it. Frowny face...