FWIW, the Classic Buckle:
I don't like how it is disconnected from the watch, where it's a normal watch strap on a bar. The leather loop (and other bands) fits into the watch itself, which makes it seemless. IMO that's better / prettier.
Also the little loop (on the buckle) where you slide the excess strap, not had much luck with them in the past and ended up breaking off (obviously not an AW, but these style straps in general) and then you have this wavy excess strap flailing about.
I think the loop is a much better design and is available in more colours and will be my "classy" strap for when I'm not using Sport Band.