Both the Class10 micro-SD card and a Kingston 133X CF card seem to be writing at 10 MBytes/sec. I doubt the SD card goes any quicker than that, but dunno about the CF card.

I'll try some reads next, and update this post afterward.

Update #1:
The same CF card in my regular USB card-reader writes more slowly from the PC.. about 8.5 MBytes/sec.

Copying a 200MByte file from the CF card to internal flash on the N7 is much slower than the other way around -- supporting my initial observation that the card reader is faster than internal flash. About 8 MBytes/sec.

Next I'll try reading from the CF card without writing to internal flash -- done, about 8 MBytes/sec.