Depends what you want it for. Capstan winches are very good for controlled movement of things... a lot of the emergency services favour them because of that.
As a self-recovery winch I would say forget it.
The main thing against them is that you have to work with a large coil of rope next to the winch, unlike other types where the winch rope is kept on the drum of the winch itself.
Being engine powered, and fully mechanical, they will happily pull all day.
