I'm helping a life coach out with some marketing at the moment.
I've got some coaching from a trainee coach to help her out as they need so many hours to get certified.
My take on it is that if you know what you want out of life, have set goals, and are generally quite happy with where you are, you won't get anything out of it.
The other side to it is if you are in the opposite situation, it might be good for you.
From an ERE perspective it's quite expensive and you could just go chat with a good friend. - for free :)
The other side of it is that if you don't feel your friends will be objective as they might have their own opinions of what you should do (possibly incentives to push you towards decisions), then again, it may be time for a life coach.