Interesting results. First off, FF 3.1 with JIT did not crash. It crashed so many times on me yesterday, that I was sure it would crash on this. Even though it did not crash, it was barely faster than FF 3.1 no JIT or FF 3.0.1. In fact, it was really only faster at error handling and the same on everything else. Apparently errors are easy to JIT for TraceMonkey!
Next, Safari 4 beta is fast. If you look at the link above, Safari 3.1 was already the fastest thing out there, so I guess this should not be a surprise. It crushed everything and it did it on the kind of tasks that real developers do a lot: array and string manipulation, regular expressions, and DOM manipulation (technically not part of your JS engine, but practically the most important test.) I am not used to seeing Opera lose when it comes to any kind of benchmark. If you throw out the array manipulation, it and Safari are pretty close.
I will have to boot up Parallels and try out Chrome vs. Safari 4 beta vs. FF 3.1 beta on Windows.