I do most of my work in ruby and am a fan of it (less of some decisions it's community makes, but I'm still okay with it)... and I shy away from rubinius because I don't think it has enough to offer to justify the non-boring risk/tax. I don't want to be discovering that some gem I use (perhaps only a couple versions after i start using it) isn't compatible with rubinius. Even if it's a small risk (and I honestly am not sure how much of a risk it is), for what? Slight performance edge? I don't need it. Multi-core parallelism? I usually don't need it, and if I do, I'm going to choose JRuby (reluctantly).