But there are some real rough edges to be sanded down still. There are places where the transparency effects mean the underlying color/text bleeds into the menu / UI text that you actually want to read. It happens way less than you'd expect from critical screen shots, and a lot of the time it's less that it makes the UI text unreadable and more that it makes it look like a graphical glitch. But it does happen, that's not great and needs to get cleaned up.

There's also a weird level of "flatness" to some parts of the UI, that seem to rely on color contrasts to get the depth, but then that means that in certain situations the depth that should be there is missing. A good example if this is the safari button bar. On a site like HN where the background is white/off-white, the buttons and their bezels just sort of look like a flat white on a flat light grey. A site with a solid dark grey like daringfireball's website on the other hand allows the edges of the buttons to give a little bit of depth, but there's basically 0 contrast between the control backgrounds and the bar background. But then a site like slashdot has a medium grey background and now the buttons not only have color contrast but the slight shading around the bottom edges gives them depth that's not present in either of the other cases. When it works, the effect is nice, the problem is their theming system isn't (yet?) smart enough to make it work all the time.