The 64GB Lexar Professional 2000X UHS-II SDXC rocks for card download. Testing shows speeds up to 300 MB/sec using the supplied USB3 card reader (also a still very good but “slow” ~150 MB/sec in regular USB3 card reader). [when copying to fast internal SSD, the card read speed is too fast for any hard drive to keep up with].
The most reliable and fastest CompactFlash card I’ve used is the Toshiba Exceria Pro—not one glitch ever.
I hugely prefer high-capacity cards (64GB) because in the field there is no need to erase them, thus they are an additional backup over and above downloading the day’s shoot (and backing that up too). Aside from cost, I’d be buying 128GB or larger cards for that resason, but for now 64GB serves me amply for most of my trips (not filling up).
The graph below from DiskTester data used the supplied USB3 reader with the Lexar 2000X 64GB SDXC card. It shows that the card is capable of sustaining very high write speeds, and even higher read speeds (a very fast hard drive might do 220 MB/sec).