So you're finding the magical miner that makes more BTC than it's initial outlay. Not one BFL device did that. Not one Cointerra. Not one Hashfast. Not one Black Arrow. None of the Avalon B3s.
THe first 2 Avalons, the first KNC Jups, and the first S1s did this.
Dragon, Rockminer, SP30s won't.
Good luck.
Add to that list the early Bitfury rigs. I've made a buttload of coins from my 4 strange, yet wonderful Bitfury rigs. And they're still as energy efficient as many of the newest ASICs.