Halili Beer came out in the early 60's, its key market being in
Manila and Southern Tagalog.
It got amazing word of mouth. How much of the hype was a
backlash against San Miguel's monopoly, I'll never know, but
my father (RIP) said it was just as good, if not better than
San Miguel Pale Pilsen. Halili also marketed soft drinks such
as Goody ("Thirst come, Thirst served") Root Beer.
SMB promptly bought out the company and buried its brands.
Lucio Tan's Asia Brewery had better luck challenging SMB, in
the early 1980's.
As for Corona, you can get it in many restaurants and liquor
stores. Rustan's Grocery used to carry it. I don't understand
why it gets a lot of buzz, as it's actually kind of meh to me.