I have a 128GB Lexar 1000x which is super fast but also over $650 per card. The speed of the card allowed my 5D3/1Dx to maintain 3fps when the buffer was full. Then I read about the Komputerbay cards on Amazon, which were $180 each. Now I always think that you get what you pay for and at almost 1/3 the price of competing brands, there had to be a catch.
Reading the comments, there were some issues with DOA and corruption, but the price point was right so I ordered 2. Testing the cards in my USB3 reader, it could read @ 150+MB/s and write around 85MB/s, which suited my needs. Now with the 5D3 been made a RAW video camera, it turns out to be the bargain CF card for 1000x memory. It can handle sustained 85MB/s writing for at least 1 minute of RAW video. Which makes it an ideal budget card for the 5D3.
I've only had them for about a month and the cards haven't failed or corrupted any files yet. I do think that the reliability and/or QC won't be up to the league of Sandisk or Lexar, but for bang for buck, nothing can beat the Komputerbay CF cards right now.