Interesting posts, from my experience , used to love Weber silver grey, 12 years ago, anything nowadays by Weber or transfix I won't touch.
For colour fastness bal micromax, all day long. Rarely patchy but a dog on porcelain. Mapei ucp on anything pale or ceramics, so quick to stabilise and settle, can finish a room wall by wall easily on ceramics.
Interesting to hear the tile master 3000 gets votes, love their levelling gear, never tried grouts, but may do now....
As far as anything grey, then gal mcromax 2 smoke wins for me, then mapei jasmine for anything else