These are the absolute pinnacle of Strap Locks in the world today. They are also the most expensive. They are very well machined, with a great design.
They've 'cured' the rattling sound that their predecessors made when you shook the strap. They sit rock-tight on the strap button.
The Strap-lock itself has a longer shaft allowing it to be used with very thick straps without having to cut/trim the strap material to make the top lock it fit, which the old ones suffered from.
Two issues though: -
1) The strap button has a combined wood tapping screw - not like any stock screw used by anyone else. It'll tap a new screw-thread in your guitar body. Be careful, as it'll often not go in totally straight, and end up being slightly misaligned when it's screwed in. I've had this a few times using these. Maybe pre-drill a pilot hole?
2) The button/knob, to release the strap-lock off the guitar, is harder to use than the old ones, which had a bigger 'handle'. These are more finicky to release.
The finish is perfect, and they're available in more finish options than any other strap-lock currently available. All in all, well recommended.