Have never done it even though its always been on my "To Do" list.
Was planning on doing the Etape du Tour from Nice next year (same date) but this would certainly be cheaper I guess!
You should do it.
It's an evolving ride.
The half-way stop, and legendary way-finding night-lights in jam-jars no longer exist.
But the number of pop-up food stops has increased exponentially, some offering places where you can get your head down, or have a sports massage, in addition to a bacon sarnie.
Southwark Cyclists continue to organise the return coaches / pantechnicons to get you and your bike back to London.
But I believe the administration is now farmed out to a 3rd party events organisation.
The number of participants has increased at least four-fold from when I did my first one (2007, the wet one).
I've said it before, but it was reading the late Barry Mason's FAQs of the DD, that persuaded me to take up cycling again, specifically, to do the DD.