It's interesting to note the time per request when you invert these. Even some of the most drastic differences (like Spring vs. Django) turn out to be the difference of a millisecond or two. That's pocket change in terms of user experience.
For instance, if you're running on EC2 hardware (which is common enough) and you're executing ~20 DB queries/request (which is probably, unfortunately, common enough), the difference between Java servlets and Rails is more like 10ms.
Then what happens when more than 89 real-world users start to hit your Rails server each second?
(Note: I really like Ruby and Rails. Much more so than Java and its offerings.)