I agree, color labels are much easier. I make notes only if the players do very unusual things.I really try to mark a lot of players but now i ve started multitabling its a little more complicated. Not only i mark them with colors but i also do the notes of why i ve marked them.
I use:
-Fish
-Worst than fish
-Regular
-Calling station
-Unsure
-Aggro
-Limper