I've used Noppoo Choc Mini (stock thick POM keycaps, Cherry MX Red switches) to take notes or code in classes; it fit perfectly on the top of my 16:10 X-series thinkpad. Later replaced it by ErgoDox with MX Clear (now vintage MX Black) switches. Never heard any complaints, although stock MX switches are basically always a bit louder than Matias Quiet "Alps", when you release them.
When the Matias compact keyboards were released, some people weren't too happy with case quality.