I don't mean this to come out as negatively as it might sound, but JRuby being faster than Ruby 1.8 isn't saying much; MRI is pretty slow.

It's still great that JRuby beats plain old Ruby in speed and also gives you Java access. The only (relatively old) benchmarks I've seen with YARV are over here: http://antoniocangiano.com/category/ruby/

... and for me, it matters more if Rails will run faster on jRuby. The benchmarks may or may not reflect an increased performance advantage for a Rails app.

Or at the very least, be able to compile a Rails app into bytecode for commercial distribution. I would have a use for that even if jRuby doesn't run as fast as MRI.

true - but at least someone is trying to fix it hehe

What Sun giveth though, Sun may "take away" at some point in the future. I'm thinking of Tcl.

Well its fully open source - heck jruby is not even hosted at sun. They simple employ a couple of contributors. There are aplenty of contributors outside sun as well.

Sure - Tcl of course kept all the contributions that Sun made. However, when the wind from Sun went out of Tcl's sails, it slowed down a lot.

true - hopefully that won't happen here - seems to be more outside influence for sure.

At least one of the JRuby committers (Ola Bini) is working for Thoughtworks. So even if Sun dropped JRuby, other companies would probably take up the slack as in this case.

JRuby makes sense in terms of enterprise software/consulting as well and probably doesn't need sun's upport to survive and even thrive (though of course Sun's support is a huge positive).