[uptown]

I recommend PJAX. It degrades gracefully for search engine indexing.

[andybak]

Yep. PJAX and it's ilk are wonderfully simple, degrade well and fit in with many existing approaches.

We added PJAX rendering to a Django site in under an hour. All the benefits of SPA's and few of the downsides.

[eddyystop]

I've started using PJAX where the rendered page does not have to change when its source data does, and where you don't have large tables/calendars that would have to be re-rendered when one data value changes.

Development is significantly faster, less error-prone, easier to maintain. Development can also be given to people with lower skill levels.