I do not particularly enjoy "sloppy" oral sex, but I like it when she gags on me and almost chokes. That I enjoy. But her getting all of her saliva on my pants? Then I get a bit mad, but at the same time, it isn't too bad.
What makes the blow job good is the movements she makes with her tongue and head, not necessarily how much saliva is there. The mouth is already fairly wet, so it's enough that it's a good amount of lubrication.