+ Clamp is rock solid and infinitely adjustable.
- Clamp (and therefore tilt adjustment) must be undone to adjust fore/aft.
(The original American Classic post was best in this regard. The newest AC posts are expensive and in my opinion ugly.
I think the patent for the original post, 4,995,753, expired and a new design was needed as I started seeing some EU companies with seatpost clamps looking identical to the AC one.)