To shared my experience ... purchased 20GH/s @ 0.16 BTC on Mar. 2, and now see an earning of 0.0054 BTC on Mar. 3. That translates to 1.69% daily yield. Of course, the rate will go down in the coming weeks, months, etc. But currently it is one of the best return one could get in hosted mining.

Also referred my friends to purchase using my referral link http://alpha-miners.com/ref/id/144. Have not seen referral bonus added to my account. Emailed support who said she was able to see my referral purchase in the database, but currently working on technical issues to reflect that amount in my account.