Prominerz is already being discussed here look at this thread from here https://bitcointalk.org/index.php?topic=5158030.0

I don't trust prominerz even the asicminervalue review as trusted I don't recommend this site to buy ASICminer.
Never heard about bitzshop but if you want to buy ASIC miner and don't want to be scam always use the official websites or go buy directly to the manufacturer because not always safe to deal with 3rd party resellers like the 2 websites above.

List of manufacturer below where you can buy miner from the real distributor or official websites.

- https://shop.bitmain.com/
- https://canaan.io/
- http://www.innosilicon.com/
- http://www.microbt.com/
- https://bitfury.com/
- http://miner.ebang.com.cn/

Don't deal again with 3rd party unless if they are verified seller or trusted seller/distributor.