I've tried playing a monk, in a party, not solo. It wasn't a very interesting experience and IIRC I quit right after the Nashkel mines.
The biggest drawback was his AC. I also remember him duking it out with a hobgoblin, with both my monk and the hobgoblin swinging at each other with no one scoring a hit for about two minutes. By that time I was gnawing at my keyboard
The hobgoblin won, by the way.