Estrella Galicia tastes way better (subjective, lol), and has been increadingly gaining popularity all over Spain for the past 6/7 years (it was known before, but now it is more commonplace).
Also, Mahou is quite common in Madrid. A bit of a shit beer, but better than Damm and, for example, Cruzcampo.
Still, they put anlot of money into marketing, festivals and stuff like that, so that might have to do with it (most beers do, though)