WTF are you guys talking about? Duel mining is still alive, because I'm duel mining eth & verg right now. You wont make alot of money anymore but with Claymores 11.4 or 11.5 eth miner allows you to duel mine Verge or Smartcash. Do some reading boys.
Dual mining heavily depends on your electricity costs. ETH dual mining eats up a lot of power and with expensive USD/Kwh, it's not worth it. Extra heat, extra noise, very small gains.
But that's just my opinion.