I prefer Blue Diamond over Masters.
In my opinion it seems to stay on the tip better and give a better grip on the cue ball than Masters, which to me is a bit too dry, and I hate that squeaky sound it sometimes makes when applying it, gives me the shrills every time.
Sometimes you'll need to wipe those blue spots of the cue ball though, but that's minor.
Downside: Blue Diamond is much, much, much more expensive.