I wouldn't mind the outputed javascript - it's unfair to compare it with coffeescript as cs is just a thin syntax layer whereas opal giver you all the goodies of rubyan oop (like, method_missing? :) ), so there is a price that needs to be paid for this. But having to drop to raw js everywhere kind of nulls the advantage. Just think of all the errors that a linter or parser could have caught, but now it can't, and on top of this add it to the inherent pain of debugging a transcompiled language and... not fun :| I liked the idea of ruby to js but this doesn't seem like an acceptable solution.