I've spent some time as well looking at virtual mining...
The outcome basically was :
The best offers are basically the cleanest "dirty shirts", meaning they do seem 100% legit but hardly offer anything close to ROI.
cex.io right now is basically costing you very roughly 50% of your investment based on ~50% ROI at their BTC/GHs price of ~0.074BTC (achieving those 50% in the end requires you to run the purchased GHs nearly until the output becomes miniscule). These figures are compensated by the GHs resale price you might achieve (which we only know will be low if you run it for >3 months). If you're lucky, you make a tiny profit in the end (if they can maintain the inflated GHs prices) but it's unlikely as it depends mostly on BTC valuation. The business model seems to work better for some people trading (presumably with Bots).
cex.io are the only winners in this game. Plus, they can and have changed the rules at their will (fees). You on the other hand don't have this flexibility, as you're on the receiving side only.
Everything not rented to virtual mining is running for themselfes at true cost, everything else is rented out for the mentioned surplus GHs price + fees. Win-Win for them, not so much for the customer.
....looks all sexy but doesn't add up as profitable for mining. Still better than EBay deals though, that must be said and in case of complete lack of alternatives - one might take a shot at it.
All the others I found had some rules or fee/business models that simply tilt the profit even much more in their direction than yours, they're made to look shiny but the small print clearly stinks to heaven.
Most methods seem based on the (apparently lucrative) assumption that customers either are incapable or can't be bothered with math. Most will agree especially beginners take some to get their research package complete and aquire a valid overview of what's out there & how it works.
Everything I found on EBay basically were blatant rip-offs that hope to catch a newbie wrong-footed.
My conclusion for now is to avoid any middle men as they only want your best : your BTC. They only seem to vary at the level of aggressiveness with which they try to skim it off your wallet.
I'd rather calculate my own hardware and take my risks.
Plus, the old wisdom
if you can't touch it, you don't own it still holds true. Bad things could happen to any of these virtual mining services at anytime, while I at home would still have all the options & the hardware.
Additionally, I'd miss my tiny mining rig
PS.
If there's a legit virtual mining gem actually realizing acceptable ROI for its customers, I simply haven't found it.
Other than that, it looks all like "shark tank with nice window dressing" to me, at times it seems just about everything BTC related is. Harsh world out there, never act without using a calculator and lots of research + common sense out there.
