I got in early too, but was considering making another large purchase, but wanted to look at some data first. Just curious if someone had down that analysis already or not
Added this to the OP
Estimated Zen Solo Hashlet ROI time in days:So currently the Zen Solo's cost 20.85 aka 0.0438 BTC for 1 MH/s. Each MH/s makes 0.00063617 BTC per day. Now if the zenpool payout per day stayed constant the machine would reach 100% ROI in 69 days. However, with difficulty increases of each coin and usually decreasing cost of altcoins the payout per day should be decreasing pretty quickly. HOWEVER, zenpool payouts on 8/21/14 were 0.00065055 BTC/MH/day and now its
only declined to 0.00063617 BTC/Mh/day which is
only a 2.3% decline over almost a full month! This intentionally does not account for the $0.08 fee per MH, which could increase in BTC amount if price goes up, or could become nearly
no BTC fee if BTC price goes up as many people are projecting.
Lets extrapolate 2.3% decline in BTC for for the 69 day projected ROI and we get an estimated ROI time of 72 days (compounding decline).
Zen Primes will need to have some cool features added to them before I believe that this will be a clearly profitable hashlet to go with. The biggest thing they could add to these right now would be the ability to mine different algorithms as scrypt already has a LOT of competition and thus lower prices. With that being said, I also expect them to increase the price of the hashlet primes along if/when they ever add the other algorithms to them, because at that point they profitability will most likely increase quite nicely