[warfangle]

And then there's situations like porting a Rails app to Lift and seeing a huge improvement in performance without touching the database / storage IO: http://lambda-the-ultimate.org/node/2147

Granted, it's not from the most unbiased source, so take it with a grain ;)

[ryah]

That has to do a lot with Ruby's awful thread implementation. You could possibly port the app again to Ruby EventMachine and see even better performance.

The point is - for 99% of people it's not the language, it's the I/O