If I may, as long as lawyers charge by the hour, there will be little incentive to improve efficiency.
I've worked with in house and outside counsel on a variety of matters. The meter makes a difference in some things, it the individual attorney or lead attorney made a much bigger one.
It works well for lots of things. After a 30 minute consultation with a new client, the attorney can estimate the documents which will be required and can give a reasonably close estimate of the total cost. It also encourages the attorneys to still track time on a per-task basis and actually look for ways to improve.
Unfortunately for one attorney I know, the bankruptcy court still requires hourly billing, so he can only do value-based billing on the stuff he can get resolved outside of court.