One thing I forgot to say above is 3-4 month ROI does not happen anymore in most cases.  It was old ROI time during like GPU day's you could count on 90 day ROI pretty much all the time.

But in today's world of BTC mining I don't think you will get 3-4 months unless you sell the miner and count it twords ROI.  Or in cloud if it's one that allows you to sell. And there is no guarantees.