How come this question managed to appear on the top page? Asking this question and expecting a correct answer is bananas. There are so many factors that you have to take into consideration that it is virtually impossible to make a right generalization. The question you should ask though, is: "What should I do to achieve goal that I've set." If your product is unstable, bugs are piling in the backlog - _maybe_ holding the factory line for a refactoring is right - but only just maybe. Remember, that users don't care about how cool your stack is.