First three seasons are some of the most rewatchable and well-paced TV ever. I love how the tension constantly ramps up and it never feels like the characters "reset" back to normal like other shows, they change dramatically from season to season and it feels organic.
I think it kinda lost its way by getting too deep into the cartel stuff and splitting up the main characters. S4 doesn't hold up like the rest do for me. But the final season was strong and the last 3 episodes are basically perfect.