Gary you ask a great question. I ran a 30 sec burst test, 3 times each for my 32G XQD, Sandisk Extreme Pro, and Lexar Pro 1000X cards. I ran the burst test because it gives me a measure of what I can do when photographing flying birds, something I do weekly. It would hold for other moving objects too, and birds which are flitting from branch to branch. You keep firing to hopefully get some nice poses.
So I pressed the shutter release down for 30 seconds and counted the number of photos I got, shooting RAW, Lossless Compressed, 14 Bit, in manual mode at 1/640 second of an all black background. Here's what I got.
32G XQD - 157 shots in 30 seconds, 76 shots before it slows down. 32G Sandisk Extreme Pro CF - 145 shots in 30 seconds, 70 shots before it slows down 32G Lexar Pro 1000X CF - 150 shots in 30 seconds, 71 shots before it slows down.
While this won't wow you, I think you'll find once I get to test the new "S series," it will, but let's wait for the test for that.
I had been using the HyperDrive ColorSpace UDMA also, but for a variety of reasons, including ruggedness, and capacity, while I can't just plug in my cards any more, but must use a reader, I'm now using a pair of LaCie Rugged Triple USB 3.0/Firewire 800 1TB drives while traveling. I like the speed of reading the photos from the XQD card. That's a factor to me.