List what hardware made you ROI and if it made you any profit.
1) GPUs: When I first got into mining a year ago I started with GPUs. ROI was suppose to be 2 months but turned into about 6 months, and the last 6 months was very little profit. However they got ROI and most of the GPUs were sold at 50% from the retail price. So in the end what looked like a huge loss turned into some marginal profit.
2) Antminer S3+: When BTC/USD crashed at the beginning of the year approaching $150 USD. I managed to get a few miners for the cheap. They got ROI very fast at just a little over a month. I am still making good daily profits off them. I bought them used, didn't pay retail.
3) KNC Jupiter: I love these miners. Many were getting rid of them locally because they are very power hungry. I love how they are rock solid, stable, and they are almost silent. I got ROI of them just under 2 months and they are still making me good daily profits. They were bought used, didn't pay retail.