The main Disadvantage of ASIC Miners is they are Only one algorithm mine-able, I think GPU miners are better than ASIC's because you can mine altcoins also .
They are good for short time but not for long run . Also Asic Miners are made for a Particular alogrithms and once the bitcoin mining has passed that certain difficulty they are basically are a piece of trash , on the other hand GPU miners can be used for a long time and can also be sold later .

Nice Post , Followed And Upvoted.