[markuz]

I don't want to start a flame war here. But why do I ever need to hit the backend? If not to save state. Logic must run only on the frontend

I don't see any need for a Rails controller. In the age of unhosted apps https://unhosted.org/, any backend based app will lose in terms of performace (the network latency will always be there)

Ruby has awful performance characteristic. But it so cute. (seriously, someone have told me this, and sure enough, they love coffescript)

Let's assume if your project works. You get $500.000 in funding and 7 months later you realize that you need to ditch Rails because of the performance.

Just one example of the perf issues I have with Ruby. Try to compile a super simple SASS file. One time it takes 0.3 sec, the next 2 sec, then the following 1.5 sec. Like WTF is happening. And it is cached !!!!