It totally depends on task at hand. If you have a db/forms heavy project than Rails/Django gives you advantage, if your project is more driven by interactions and subtle UX then SPA lets you focus on that.

Like, imagine how hard it would be to make Shopify as SPA (https://engineering.shopify.com/17489056-rebuilding-the-shop...). On the other hand, Trello would never feel so fluid if it was driven by server rendering (notice how weird Github projects comparing to Trello).

Personally, I've been doing SPA for years and think it's the right way for reach UI. But recently I had to build a form-heavy app and decided to go with classical server-side setup + some jQuery on client. Old school but very productive.

EDIT: added link to shopify blog.