Don't buy the Bitmain Antminer E9! It's mining Ethereum, and we all know that it will go Proof of Stake in early 2022, then you not able to mine Ethereum. The ASIC can't switch to other coins that GPUs can. Well, you actually can mine other Ethash coins. But they are very low cap and has low net hashrate compaired to Ethereum, so your profits will plumber!