That screenshot is pretty old, from Xcode 3, back when I first switched to TNR. I have no eye for kerning, so it didn't bother me then, but it looks a bit better in Xcode 5: http://i.imgur.com/rRxUpDY.png (included quoted text "CHARACTER SPAWNING" so it can be a/b compared).
The comment is the only thing in a monospace font. It's a criticism, and a valid one, of your choice of programming font. Nobody in their rightest of minds programs in Times New Roman. I'm convinced you must be trolling us.
I also use proportional fonts for Java to make the code look like it's taken from an algorithms textbook. Also, idiomatic Java as produced by IDEs usually doesn't align variables, so the code looks OK as long as the space characters themselves all are of the same width.
The C++ code I work with usually has more strenuous alignments which are only possible to get right in monospace fonts.
My main problem with proportional fonts is not alignment (I don't really do that beyond the indentation) but symbols. Most proportional symbols, especially thin ones like dots, colons or the vertical 'or' bar, get too packed in between letters and can be hard to see. Since reading code with precision and ease is the most important trait I ask of my programming fonts, proportional fonts are out. But I'm open to suggestions about one that works.
