Mid way through the book. Very good read. I wish we had it a couple years back. But its never too late. As someone said definitely a good way to get marketing mindset. I would read it along with Lean Startup and go in with the right tools.
Lean Startup struck me as very much in the Business Book mold. The concept is a good one and he spells it out well, but there's really very little there that's of much practical use if you've mostly already bought into the concept.
Am reading Running Lean, Traction, and following growthhackers.com - heady mix :)