I got to try out the electronic DA at a show last November. Shimano had it mounted to a bike on a trainer, and there was a long line of folks having a look.
The appearance is chunky compared to fully mechanical, but I thought it looked nice enough. It worked quite well with the most memorable feature being how the front derailleur automatically keeps the chain centered in the front cage as the rear is shifted. The front shifting is apparently much more robust against the chain falling off. Also, activating shifts by just lightly pushing a button on the brake levers was sort of neat.
Even so, whatever the price, I still prefer fully mechanical.