There is a lot to look at, and I recommend you take a gander, but I wanted to highlight this paragraph:
JRuby is truly impressive, being the only implementation that’s able to pass all the tests without raising errors or timing out. Not only that, but in my previous benchmark, JRuby was several times slower than 1.8.5, whereas now it’s faster than the main Ruby interpreter. There have been huge improvements going on over the last few months. Really, just compare the times in the old table with the ones in the new table: unbelievable progress. JRuby is the only one, aside from 1.8.6, which is able to run Rails in production. I wouldn’t be surprised if JRuby turned out to be, on average, just as fast as Ruby 1.9, in a year or so.That's some pretty impressive news. Kudos to Charlie, Thomas and the entire JRuby community!