Works for the most part
I have been pleased with the way it works with my MacBook Air running 10.9.3. Calls are clear. There is a bit of an echo on my end but so far nobody can tell that I am talking to them from my computer.
The only issue and it is annoying is that the app doesn’t reconnect to my iPhone when I come back into the office without a hang or two. At that point it locks up my computer for several seconds.
papafrank about PhoneBox - handsfree, recording calls for smartphones