Performance in the camera:
I have used no wissenschftlichen methods to measure performance in the 5D Mk II. Subjectively I can say that the burst rate is significantly higher when only RAW images, as I previously knew of my SanDisk and Transcend cards. If, however, for me not so very relevant, because I with my camera rather than turn to Scan 4-fps movies by automatic fire ... ;-)
Performance in the card reader:
Here I can do much more objective, as reported on the basis of benchmarks testable, by the incredible performance of the card. The Lexar card reader depends on a USB 3.0 port ASUS U3S6 PCIe card. The benchmarks that I have created with ATTO, show that the card allows data throughputs of up to 123 megabytes per second when reading!
Here's a real example: Copying 212 image files with a total of 0.98 gigabytes extent on an SSD has exactly took 10 seconds, which is almost 100 MB / s. My 16 GB Transcend 400x CF card it creates on the same card reader to no more than 35-38 MB / s.
Conclusion:
I am of the Lexar 1000x card fully convinced and would buy again at any time. Annoying is that I had to pay as "early adopters" for almost 70 euros more than is required today from Amazon. Does the thing could not be stopped as long as I'm so happy with the product ...