I've often heard the comparisons between Breaking Bad and BCS, but I feel like both shows are an extension of their central focus.
Breaking Bad went from a dark comedy to a chilling drama as Walter White lost aspects of the doofus school teacher and transformed into the venomous, treacherous monster he was by the end. It's upfront, it's not subtle about it because White was never genuinely good at being subtle about it either. Whenever steered into the topic on the show, White would always slip up and hand a clue over to someone he really shouldn't have.
Better Call Saul is on the surface a comedy, but there's a much darker edge to it just underneath the surface. It's very much Jimmy/Saul, who greets people with a smile and a joke, and a laugh but can be something of a monster himself underneath all of that window dressing. It lulls you far more than Breaking Bad did before it goes for the gut punch.
I love both shows, but man, I really think after this season Better Call Saul might be my favorite of the two.