Bitcoin used to buy ASICS - RISKY (as most will never get ROI on their bitcoins)
USD to Asics - less risky (with btc price going up this can attain ROI with a higher chance -however, you could be able to buy more bitcoins with the cash you used to buy the asics)
risk risk risk
Many got ROI very quickly after receiving preordered unit. The key is to have the device soon, but this preorder game is like gambling