Fair enough. But I meant "fast" relative to Ruby 1.9.2, not "fast" relative to anything else. The "require" issue aside, REE beats out 1.9.2 pretty handily in a lot of real world situations. I've seen 1.9.2 win in microbenchmarks, but I haven't actually seen it perform better on a real app yet. Obvious selection bias there, but the point really being there's no compelling reason to upgrade.