How many of the "GC is always slow" people would recognize those systems? Besides: V8 and JSC have pretty decent JITs nowadays. IME, performance of JIT systems has more to do with the structure of programs written in JS than with VM performance itself.

Maybe I don't know what I'm doing, but I rarely get performance within an order of magnitude of single-threaded C from V8. In those other systems I usually do, unless you count Java's startup time.