GTX 1060 3GB for $190: good deal?

It is shipped and sold by Newegg so you can RMA it no problem. The lack of reviews means nothing, they are all pretty much the same in that price range.

The thing with MIRs is they tend to take a long time to receive (if ever, still have 2 out from last year I never got. Typically they take a month or more to even start processing it). If you are strapped for cash, a MIR doesn't really help. So pick the one you like more and don't count on the rebate to ever show up.