I have two Delkin readers, one for CF Express B only and one for CF B and SD. both have worked good for me, but the doors have broken off both. Crappy design, but still work fine.
I have the much larger Prograde B/XQD that I leave hooked up to my desktop and the other two are for travel.
I recently picked up a new Delkin USB4 Type B reader for a desktop replacement. I states speeds up to 40G, but I have not tried it yet. While I can speak to the new on yet, I think it might be one to look at if you are interested in faster speeds.
For size comparison.