Regarding the debate over mechanical versus electronic…
The best shifting mechanical group I've ever ridden was a Shimano Ultegra 6600, on a bike which I built myself. No mechanic was ever able to tune that bike better than I could!
Currently I'm riding Shimano Ultegra 10-speed Di2. From my perspective, the best thing about electronic shifting is the automatic trim feature of the front derailleur. Although I know the idea of electronic shifting is that I can change gear with a simple touch, I miss the ergonomics of the manual shifting and wish that Shimano had retained that motion in the electronic levers.
I understand that SRAM is taking electronic shifting to the next level, in that their group will be wireless!