Except that at least a gear looks like an icon, which suggests it might be clickable (since the flat-design people thought that making buttons look like buttons was a bad idea). My problem with the hamburger menu is that I literally don't see it, because three horizontal lines does not look like an icon to me, it looks like a decoration. In pretty much every place I've needed to use it I end up going "hmm, where is [essential feature I can't find]?" Nowhere? Not possible! Oh, yeah, those three lines, that's actually a menu. Yep, there it is.
