I have made my money back with 5MH/s but I bought it like 5 months ago. I do not recommend getting 5MH/s now though as the difficulty has gone high enough to not get payouts to your wallet everyday. I now have to wait 2 days to get my payout. When I first bought it I got payouts everyday. On June 13th the difficulty was so high that I no longer was getting payouts everyday.
Since this is a 2 year contract though I would imagine you will make your money back. I suggest if you are going to buy X11 keep buying upgrades with fiat until you get to just over $30 dollars a day. After that keep buying $30 upgrades everyday. As long as you keep feeding the beast you will be good. The problem with it though is that you will need to get past $60 a day for upgrades before your first contract ends because then you will be losing hash power so then you will need to pay double for your upgrades to keep upgrading. 2 years after the $60 upgrades you will need to do $120 upgrades. So on and so forth... It can be done but I don't recommend it.
I prefer SHA256, as the above method need not apply other than paying fiat until you can start feeding the beast from the payouts each day which would be adding 6TH/s a month. That will create exponential growth and keep you really far ahead of the difficulty increase.
Stick with SHA256 that is where the money is...
RE: X11 Mining