Earlier quoted context omitted.
I made the same switch. I had a Linode 512 and switched to a 2x512 Dropplet setup and put my Database on one 512 and my Rails app server on the other. My stuff runs as quickly if not quicker and I spend $10/mo less. In addition to this I also have a clear scaling path (e.g. If my DB grows I can up it to a 1gb. If my traffic grows I can either move the app server to a 1gb or maybe get a few more 512's and setup a load…
My one complaint with DigitalOcean is that I had a dev server setup and I was snapshoting it and destroying it when not in use then recreating it from the snapshot when I needed it. A few weeks ago they had a failure of some sort and my snapshot was lost. It took me a fairly long time to setup the dev environment so I was a bit pissed.
I do this with Linode stackscripts, and I couldn't live without it. Unfortunately DigitalOcean don't support stackscripts as of yet. And their support didn't want to tell me if they will ever support it.