I think there may be a bug in the menus of the Method preview sites on OS X Lion. After a few minutes of browsing, the text of the drop down menus disappear—the menu still drops down, and its links are still clickable, you just can't see the text.
I've seen this in Safari on OS 10.7.0 and 10.7.1. I haven't seen it on my own site, but I don't have many menus in place yet. I haven't tested any other browsers or OS for that.
Also: I've made a few minor customizations (changing the size of the slider, tweaking the font stack)—will I need to make those over again each time you update the theme? And how will I know when theme updates are available.