Believe me, i have calculated nights and nights, but to be honest, with current difficulties, asic miners now and the upcoming 400Gh/s miners, the time is almost over to mine for profit. And you do know that when you buy from BFL that you will receive your order in about a few months? I have ordered one in April and it is still not here.
As a small stockbroker i would say...buy for that kind of money bitcoins...they will raise in the second quarter of 2014 like a mad man