Earlier quoted context omitted.
Rubinius is using it successfully though (I think anyways, does the Ruby community have benchmarking infrastructure?)
Yes. My impression is that it's the same kinda-sorta successfully as Unladen Swallow - pretty good, but nothing like LuaJIT2, V8 or SpiderMonkey.
Apparently PyPy still has work to do, we must insert ourselves into this list!