I am not entirely sold on “isomorphic” code. While it might be handier to have your full stack in one language, I would argue it’s less common than we think to have people working both in the back-end and front-end. Even if the gap is closing in between the two, they still focus on fundamentally different concerns. I think “Isomorphic” code can be perfect for small teams with people actually doing full stack development, but for larger team I have the feeling this can dangerously blur the line of concerns; the same language gives a false sense of similarity/ease to the developer while he is attacking orthogonal problems. This really is just an intuition, as I have never worked with a full blown JS team before. ;)