It’s generally considered true that two heads are better than one and the whole is greater than the sum of its parts. Sorry about the cliches!
A good coach helps you think outside of the box and will make sure you keep your goals in mind. Having the viewpoint of an outsider is hugely beneficial as we often get bogged down in the minutiae of day to day matters and forget the bigger picture.
As for being too busy to have time for a coach, can you really afford not to make time? Most business coaches will coach by telephone if you can’t spare the time to see them, so it is not too intrusive on your day.
I’d be really interested to hear of experiences both good and bad!