Docker Registry - local or hosted?

Today, amongst endless emails, proposal writing and fretting about the future (in a broad sense), I've been contemplating the relative merits of having a local Docker Registry as opposed to the out-of-the-box central one provided by Docker.

On the one hand its nice to be in control and on the other it does mean additional overhead. I concluded that I needed to do some research to weigh the pros and cons so I'll post my eventual conclusions here once I've had a proper chance to investigate more fully...

UPDATE: I've just seen a good article which nicely posits some answers...still mulling though..