[JonnieCache]

>I think the point was that you should be able to flip a switch and get mongo in a fully functional Rails stack just as easily as you flip a switch and get mysql (sqlite being the default).

Mongoid, the premier mongodb rails adapter, has fully functioning model generators and its API is built on ActiveModel, the same as Rails' own ActiveRecord. Thus it is fully compatibile out of the box with the majority of other rails components, such as form builders and authentication systems.

It doesn't really get any more 'flip a switch' than that, even in the world of rails. Since 3.0 rails has been decoupled to the extent that other db adapters etc exist pretty much on an even footing with the rails defaults.

EDIT: apparently the mongomapper adapter also uses activemodel these days.