My only complaint with infinite scrolling is that it breaks the scroll bar. It looks like Google accounted for that here by pre-rendering placeholders so the scroll bar doesn't keep resizing and jumping around. (But this wouldn't work so well if they had, say, 10,000 fonts.) Waiting for dynamic content to fill in the placeholders is no worse than waiting for a new page to load.

I just wish we had a standard "lever" widget to replace the scroll bar in lazily loaded pages - similar to the middle-click scrolling on at least some systems that have middle mouse buttons.