My first USB-3 CF reader was the Lexar dual slot. It was unstable as hell, often being invisible to the system, or slowing inexplicably to USB-2 speeds and simply not recognizing three of my 2 year old Sandisk cards. A colleague had similar issues and both readers are now landfill.
Next I got the Sandisk Image Mate. http://www.sandisk.com.au/products/readers-accessories/imagemate-all-in-one-usb-30-reader/
which thankfully can be detached from its bizarre looking stand. It's been 100% stable and blindingly fast. The new 32Gb Lexar 1000x cards scream down in 30 seconds less than no time.
However there is an issue with this very compact piece of hardware. The "throat" of the reader where you insert the CF card is very shallow, and the CF card is not always guided directly onto the gold pins. I have bent pins in the reader on half a dozen occasions. It's easily straightened with a very fine jewelers screwdriver, but it's far from an ideal situation.
Still on the lookout for the perfect USB-3 reader....