it might ROI if purchased in Bitcoins depends on how the difficulty escalates, if purchased in dollars it will ROI, but it is also true that purchasing the Bitcoins would have been better investment.
buying a miner is a very high risk investments that can have high rewards, in case of loses they will not be very high, unless if you purchase from BFL and get the miner a year later.
Hindsight is 20/20, therefore I think you got it backwards my friend. If purchased in dollars, you will ROI. If purchased in BTC, you'd be better off keeping the BTC last June/July/Aug. You would have made triple if you just kept the bitcions last summer. You would make nothing if you just kept the dollars.
Yes, purchasing the bitcoins would have been better. 20/20. Heck, I think purchasing them now would be better than getting into mining. They could be 1000 in a year. Who knows. Yes, BFL sucks. They're an expensive lottery ticket at this point. I will be solo mining with mine soon.
1 Jupiter would cost ~60 bitcoins last summer. If you had a day 1 order, you'd have made ~20 at this point. Maybe 10-20 more before next couple dif changes. So all in all better to not buy in bitcoin last summer, but buy in USD.
IMHO