[janko-m]

Yes, multiple databases are really useful for me, for some reason I often need to transfer data from one to another, e.g. legacy database to a new improved one (which I think happens often if you're in a non-startup).

In ActiveRecord you would have to specify for each model to which the database to connect. And then you have to figure out how to call a User model in one database, and how in the other (you have to call them differently, even if table names are the same). I think it can get pretty chaotic with something bigger.