I turned off all my S1's in October 2014. And sold them all in November for almost what I paid for them. So in the end, I got my ROI plus a bit of pocket change. I would say it's a good experience on learning about Bitcoins and mining, but I won't be doing it again any time soon.

I still have two modded HP server power supplies that I don't know what to do with. They're only worth about $10 or so on Ebay.