Some of us who have been using Cherry MX blues for a year or more can tell the blindfold test between Kailh, Cherry, and Gateron pretty easily.
The Kailh just feel cheap compared to the Cherry or Gateron. They are gritty, slide back and forth on the stem pretty bad, and bottom out with a lot of reverb (prolly due to the springs and maybe cheaper casings).
Gateron compared to Cherry feels smoother, no grit, much more linear, more tactile bump, less "click" noise. The design of the sliders in the Gateron is very different compared to Cherry.
The Kailh is just a cheaply made Cherry. Howveer, given the quality of Cherry in the last couple of years.... it may be indeed hard to tell a difference given the drop in quality.