[bri3d]

The whole point of electronic gear switching is that there is no slack in the lines - the shifters communicate wirelessly with the derailleur and the derailleur uses a small motor to execute the gearshift. It's actually awesome in practice - gearshifts are crisp and perfect each time, without the need for frequent adjustment or dealing with issues such as cable stretch and dirt. The batteries last a few months and if they die, you're stuck in one gear (you can change it at the side of the road with your hands if you get stuck in an undesirable one) - no big deal.

For a commuter / daily-driver bike without weight concern, I think a belt-driven internal planetary gearset with electronic shifting would be ideal as the bike nearly becomes a sealed unit, without any exposed grease or need for lubrication or adjustments.