Very nice and subtle use of gradients. Also like the buttons and their icons, especially the shadow effect. They scale pretty well with the font size, even at ridiculously large or small font sizes. And a very often overlooked detail, the buttons on a maximized window actually go all the way to the screen corner.

With the "Splint" sub-theme, shaded windows look good as well, I didn't really expected otherwise, as the title bar already is already design-wise separated. For the others, unfortunately, shaded windows don't look quite that polished. There are "gaps" where the window frame would normally continue. But really I'm just nitpicking here ;)

All sub-themes pick up the colors of your Gtk theme and also work pretty well with darker themes. The title text color is "hard coded" to white, so the text-with-border effect works even for those themes that have a light background, dark text color for selected elements.

I find them all to be very useable, very unobstrusive without being bland. They all fall right into the style of other Tango-ish Metacity themes, very similar to the Clearlooks variations that ship with the latest Ubuntu. The only wish I have is for a rectangular version, as I personally don't like the rather large radius used by Metacity for rounding window corners.

If I could give a rating, it would be a 8/10. Nice work, thank you for sharing!

(Out of curiosity, which way did the evolution of these themes go, back to front or reverse?)