mseaworthyIf I see correctly each vertical row have the same type of switch, whereas the horizontal row has the same keycap-material. The sound changes depending on the keycap material. The click of the keycap with the "S" sounds much sharper and annoying to me than the key below with the 5 petals. And the tactility will probably feel a bit different too.
And to be nitpicky the reviewer should have used them in an actual keyboard as the sound resonance on a hollow acrylic something plate is different than on aluminium or on other surfaces.
All of those factors which can change a nice click to an annoying shrill.
https://www.youtube.com/watch?v=B2muXU_CEtM