Agree with weblover ... though in this ridiculously complicated world in which we live. That answer can change depending upon someone's goals.

Quality content = Actually useful to human visitors. Makes the site more valuable and useful to the actual userbase. And supplies them with an incentive to use it/participate and return.

Quantity = May be noticed and indexed by search engine crawlers. Therefore get indexed more, ... or even assigned a higher SERP position. Even though its trash in/trash out.

Best of both worlds ? Quality + quantity = Houstan all lights are green .... we are cleared for take off. Roger that, see your website in outer$pace.