2 is the best, I haven't seen 4 yet.

John Wick always was a comic book concept. The first one tried to play it straight, and was more art-house-y, but I felt like the suit hadn't quite fit yet. 2 turned the franchise more to its pulpy influences--fun but it wasn't completely ridiculous yet. 3 is when it really started to go ham on the lore and backstory, which is great for fanboys who love that stuff, but imo it made a simple, streamlined action franchise more closer to the average mainstream blockbuster.

Also, Halle Berry was just awful in 3