So, first of all, in any discussion about the "best" anything, you need to define your criteria. For the best watch brand, my criteria is some combination (in no particular order) of craftsmanship and prestige among WISes. I also tend to filter out some of the way smaller independent watchmakers, mostly on the prestige grounds, since they often seem to lack a certain critical mass of regard among the WIS community.
I disagree. I'd put PP and ALS at the same level, with PP being a bit more of the classic pinnacle, and ALS being a bit more of the new comer/challenger. And I don't think Audemars is in the same class as PP or ALS.
I also tend to put Vacheron below PP and ALS, though above AP. I do give them some special regard, similar to that which I give to PP and AP -- I sort of view VC as the elder statesman of horology.