You can't compare turbolinks and Ember.
Turbolinks and pjax were designed to give a performance boost AND keep the standard Rails development stack e.g. server-side rendering of views.
Ember is designed to remove this server-side generation of views / forms and treat the server as nothing more than a JSON API.
There are times when both approaches make sense but more often than not I feel that server-side rendering is superior, in development experience, testability, stability, routing, SEO. Server-side rendering of views is much simpler, faster to develop etc.. The only benefits of doing everything on the client is a theoretical speed boost. To me, that's not worth the problems you encounter with it.
I'm not completely opposed to client-side heavy applications, I feel that a framework like ember shouldn't encompass the whole app though, save the client-side complexity for when it's really required and only introduce it when there's something when the server-side development wouldn't suit.