Do you heared anything about baikal miner? And as I know Baical Miner's company isn't scam but their miners are very expencive, their cost starts from 500$ and up, on amazin you can buy it in 800$.
I personally don't have experience with this miner but the company as I know isn't scam but now I wouldn't risk to pay 500-800$ on it.
You can find more information here: https://www.dash.org/forum/topic/hardware-discussions-asic-gpu-cpu.101/ or here: https://bitcointalksearch.org/topic/asic-baikal-x11-x13-x14-x15-qubit-quark-dash-mini-miner-1568973
Well, it may not be a scam but it's still a bad deal, it may be profitable right now at current coin values but in a few months who knows, and you need almost a year just to recover the investment, at current market values...