Has to be Bal everytime. Unless the customes has supplied their own. The as long as it's not the ready mixed stuff i'm happy to use it. Many of my jobs the the grout is always recomended by the manufactor. Then U get no come backs.
Currently in flux at the moment. Started out using BAL but trying Ardex at the moment. Found BAL microflex wasn't giving me pleasing results, so I am trying something else. Not been in the game long enough to decide what I like and don't like really. Will carry on trying stuff as the requirement comes up.
One of the independant tile supplier's I buy my material's from has sample's of mapei, I tried the grout for the first time it go's off faster than any I've used before but got a good finish, hope they decide to supply mapei