Not sure...... what puts me off it is the number of wires - they look somewhat messy at the moment, and I couldn't be arsed with charging the battery. There's a junction box up near the front shifters, then another mass of wires down near the BB/front shifter...
Although something of a Shimano fan, I don't like the look of the new DA 7900 groupset - not half are pretty as the 7400 - 7800 series.
I'd also think that long term, this system will be costly to run - motors do fail, and say three years down the line, you may be faced with a £350 plus bill to replace a mech.
My current preference would be for Super Record..... Don't forget the Shimano stuff is getting rediculously expensive at the moment due to exchange fluctuations.