Amongst the big three (no not the basketball of the 80s or the present, nor is it the big players of the second World War, or do I know much of golf), there are other well established extra virgin olive oil producers in the world, but hardly not as qualitative or quantitative. For this purpose, I will outright make the claim that the Greeks were the first to formally establish olive oil back back way back in times of the Minoan civilization. And before Caesar made a name for Italian civilization, there were the Etruscans, the prehistoric Ancient Italian civilization not known to many, but the first to officially refine in the qualitative form to what Homer calls “liquid gold”. As we (mostly restauranteurs and buyers) know, Spain has lush amount of land to cultivate more than Italy and Greece combined under a much more affordable price; basically the ability to mass produce. If we examine these labels under another light (perhaps a bit biased and condescending) we could view Greeks as the Americans, in starting something, Italians as the Japanese, always perfecting that something, and Spaniards as the one to always mass produce under lower expense, which I will let you fill in a country of your choice. ;P
Now don’t be offended by my arrogant metaphor, but do understand the players in this war between superiority within quality and quantity. Although Spain does have many quality oils (as do Greece), eventually it’s all about personal preference. In my experience, Spanish oils has mostly been undercutting Italian imports just as Greece are as well. As a matter of quality and techniques, they all vary just as there are rotten apples in every bunch. As for Italians, there are those that are stupendous, and there are those that are inferior. No matter where you choose, there will be a few obsolete brands. And as of taste, they also vary. There are absolutely no “better than” by country oils. It’s simply just preference.