When I consider the amount of Zelda games and how much I like them on average, it's definitely my favourite single-player focused series. I specify "single-player" because I find it way too tough to compare them to multiplayer-based games, such as Splatoon and Smash.
Of course, there are plenty of franchises that have a game (or games) that I like more than a majority of Zelda titles (eg. Metroid, Mario, Crash, Kid Icarus, Rayman). If I were to make a top ten list of my favourite games, there would probably only be two Zelda games on it at most; Zelda just has the edge over all the others for the numerous top tier experiences.