the AMHash price isnt that good - Its effectively 1.2BTC/TH (prismas and similar gear are about 1BTC/TH), with maintenance fees around $0.07/kwh. (prismas use 0.7w/GH). Its pretty competitive with the alternative, but still requires certain key factors to be a positive ROI.
Im not saying it is. It was in response to Mabsark who got the maintenance fee wrong by over 8 thousand orders of magnitude. If it was as he thought it was, maintenance fees would effectively be zero, and I certainly would be willing to pay 1.2 BTC/TH with free electricity forever. OF course thats not whats being offered.