[Matt]

Angled. A "no roll" feeling back and through is extremely easy.

With horizontal, there's plenty of room for error when swinging it open and then rolling closed. Not to say it can't be done, but it's difficult. On longer putts many people probably unknowingly horizontal hinge because of the longer stroke.

I've tried vertical, but no longer use it. It's nice because the face is always square to the plane line and target but the fact that it's a deliberate manipulation outweighs that benefit. Do you really want to be thinking about reverse-rolling on a downhill 6-footer to win a tournament?

Even so, the angled hinge with a putter is more towards a vertical hinge. As the club gets shorter and you get more "over" the ball, the "no roll" feeling of the angled hinge produces more layback than closing. Think about it on the other extreme - with a superlong 50" driver and an angled hinge, you're on a much flatter plane and "no roll" tends to be more closing than layback.

After looking at all of it, I believe angled hinging is the best to use. First because it's such a simple feel, and second because it's almost essentially a vertical hinge with a putter (but without the concious manipulation that vertical hinging requires).