People who say anything about not meeting ROI are ignorant. How can you comment on ROI when you have no idea what the cost of bitcoin will be next week, next month, etc.
You should measure your ROI in BTC, not $. I paid 1.5 BTC for these 2 S3's. I am doubting they will end up mining that much. The fiat value of BTC now or after 3 months of running these units matters little to me.
I think once you are in the crypto world long enough or deep enough, you start thinking of the cost of everything in BTC. I am about to buy a house, only 30,000$, so a steal really. But my mind immediately did some quick math and I thought "shit, this thing is gonna cost me nearly 50 BTC. This will sting a bit".