I've watched videos but haven't used one myself. They're neat winches but dang they're expensive. Northern Tool has a 1 ton with a Honda engine for $1500, and that doesn't include rope. A good winch rope isn't cheap, either.
One thing is the weight rating. A winch on a truck is rated for a rolling load up an incline. A 5000 winch will pull a rolling 5000 lb load up something like a 20 degree slope (or maybe is 20%, I'm not sure). It won't deadlift anywhere near 5000 lb.
OTOH, a capstan is rated for exactly what the line pull is. A 2000 lb capstan will deadlift 2000 lb.
