bitflipper
No fancy GUI, but it's endorsed by a well-known Las Vegas entertainer. No, it's neither Sigfried nor Roy. 

Barth Grooks!!!!!?????

Elvis?

It's a lot of fun to double track vocals...I could see where you might want this for a paying client to save time, but I would rather sing the part.

You ain't as lazy as me.  Heck, nobody is.

I dunno, ol' pal. I've got a black belt in lazy, too. But I refuse to use fake double-tracking unless it's a down-in-the-mix BGV or something. 
 
I've been wondering about which Beatles songs the original ADT was actually used on. I'm thinking it might have been a small minority.

All of Ringo's songs.

clintmartin
It's a lot of fun to double track vocals...I could see where you might want this for a paying client to save time, but I would rather sing the part.

If I sang both parts it would still be the same "bad" vs. using a tool to do it. Bad is as bad does.

http://en.wikipedia.org/wiki/Automatic_double_tracking
Actually it was on more than you'd think.  And for more fx than just "double tracking".  And by more folks than just The Beatles.  It's a fairly useful tool.  But useful is as useful does.  And life is like a box of chocolates.
 
 
 
PS:  I do most all of my "feaux" double tracking with Melodyne.  It works a treat.
 

So, I gotta spend 99 shekels then?