The grey Cherry switch is just like the black one (linear action) except it requires a stronger force to be depressed. So it's normally used for the space bar, as in the photo. I have a black linear Cherry board (similar to the one shown except it has a trackpad instead of the trackball and it's all black) and it had a grey switch too below the space bar.
Regarding the white ones, I have a board that uses those exact same switches. They are clicky, and I quite liked it except that (I think due to the usage from the previous owners) some of them lost part or all of their "clickiness" and have become pretty much linear now.
Just like those in the photos, my Cherry whites do not have the brand on them, so they're either fakes or a very old model (maybe at that time Cherry did not put their brand on them?!).