I've tried all kinds of calculators for mining equipment and all come up with different results. I would get into mining if I knew I'd get at least 90% of the initial investment. One I am very interested in is black arrow both X-1 and X-3 look tempting and seem to be shortest to the market but as everyone said mining hardware is a gamble when it comes to preorders. So right now I am researching and souring every piece of information as to which piece of hardware to go with if I decide to do so(yup very indecisive until moment I commit which has cost me a few opportunities so far but not anymore).