With the current available technology, if you where to start today what hardware would make sense in order to be profitable. All the simulation that I make only show that current hardware is not profitable (S5, S7 included). With M20 you can make profit the first year of operations....
Not 'maybe' a scam. It definitely is. The S7 is the only miner available right now and it's twice as efficient as the S5. These things are saying they are .06 J/GH. I bet they're using that number since KnC promised their next gen chips will be that low as well...but nobody has seen them and they keep it all to themselves anyway.
Bitmain has been able to squeeze out major efficiency with their chips and when/if they go 16nm, they would have to beat their current gen to entice people to buy.