Currently using Predator. In the beginning was nice because I didn't have to chalk as much as with the Masters. But I find myself chalking every shot, so thinking of going back to masters as I do not see a difference between them when I chalk every shot.
I use whatever chalk is available (usually Master) because if you chalk before each shot, it really doesn't matter (although, the new/fancy/expensive "sticky" chalks can cause more-frequent cling, which is not a good thing). For more info, see:What kind of chalk do you use and why?
Interesting that people still distinguish pre-flag from post-flag when there's zero difference between them.Triangle or PreFlag Masters