So I have mined 1 ZEC at almost exactly a week of mining.  Based on prices I can say that 11 ZEC would definitely put me over 100% ROI so 10 more weeks.  I know it won't actually be 10 weeks, it'll certainly be longer, but that looks pretty good right now.  Reminds me of the old days of the early antminers when you could actually make a profit in the long run and ROI was under 6 months.