What concerns me about these opportunities is the combining hundreds or thousands of people investing throwaway money, which ends with the potential scammer making tons of money. Each individual didn't lose much and can write it off as a high risk experiment, but that's what makes the scam so great. I'm not accusing you of a scammer, but I wish these mining businesses had minimum commitments of $2-$5k from each investor with the mining business having complete transparency.
I have no problem buying 1 or 2 of the $120 shares, but I'd much rather throw you a few bitcoins for 20-30% of a single miner.