I think there has to be set a difference before starting the old talk about La Liga vs EPL again.
Most popular does not mean the best quality. And also the best quality is difficult to estimate when a league has better top teams, and the other one has better lower table teams.
La Liga is probably known as the best league in the world, with the best players and the biggest clubs (Barca and Real are 2 of the best 5, with Bayern, Milan and Manchester United possibly being the other 3), while EPL is probably known as the most popular league in the world as well as the most spectacular to watch overall (just my opinion).
Barca and Real are the teams that make La Liga the best league in the world. There's not much difference between Tottenham and Sevilla, or Villareal and Everton let's say. But Barcelona and Real are usually better than England's best. Sure, there can be exceptions, like Liverpool smashing Real 4-0.
England has the best fans, the best atmoshpere and the dinamic of the games is better. Less tactics, but few people are very interested in tactics, most prefer prefer the philosophy that says: "I'll attack, you'll attack and let's just see whose day is today. My day or your day". End to end football is considered more attractive by most of the fans.
Also, most of England's stadiums are packed. If you see a Swansea - Stoke, the stadium is full. If you see a Getafe - Almeria, it's 70% empty. I for one, don't feel like watching a game which almost sounds like it's played behind closed doors. That's a true indicator that, actually, brittish fans from outside the central football-areas like Manchester and London, care for football more than the Spanish equivalents usually do. Stoke fans and Swansea fans are way more interested in their teams than Getafe's fans for example. More passion. That's what makes the Premier League a more spectacular league overall. Fans are more passionate, and it's almost like a duty to support your local club, a sort of tradition given from generation to generation.
Also, let's not just disconsider money distribution, which means better players for smaller teams (FFS, Newcastle, a pretty average team in England these days, fighting relegation, just transferred one of the best Dutch talents in Wijnaldum). Getafe won't evern come close to buying or attracting a player of that caliber. They usually transfer free players and sell for 3m to be able to at least survive in the first league. La Liga is like a league of three dimensions. The title fight, which is for 4-5 teams at best, depending on the period in time (Barca, Real, Atletico now, in the past, Depor and Valencia were in the mix as well), the Eurppa League spots are also a duel consisting of 5-6 teams and the relegation fight, which also involves 4-5 teams usually.