The electronic shifting groups are a step up from the mechanical, IMHO. The new Dura Ace and Ultegra groups supposedly have really great front shifting due to a redesign of the front derailer (derailleur if you prefer).

I would really like to spend the cash on a Dura Ace groupset, I love the way the new 9000 stuff looks and apparently it is mechanically awesome too, but then reality takes over and I realize I am probably fine with 105.