Thanks Frank it's helps a little ... I guess the calculators do not take into account future exchange rates between btc and $$ which would be hard to do even if it's a guestimate.
I guess the real question is - if you had the spare money would you invest in 3 x Prospero X-1 and expect to get your money back + profit?
I'm not familiar with that brand, I'm hoping to get a KNC miner when they release their next lot. I do think mining is still a viable way to make some money.
When Bitcoin was first mined, it was practically worthless: electricity + equipment would vastly outweigh profit, but look at them early adopters now. With Bitcoin having the potential to capture 5% of the FOREX market, giving it a potential value of 1000000$ per coin someday, I'm not giving up, lol.