I watched all of this recently and I have quite a few thoughts that I am now going to throw at the wall like shit and see if they stick.
I'm not hugely invested in the show itself, per se. I more like what it represents, which is an enormous number of well represented minorities and people you just otherwise don't see on TV.
I also like the way it refuses outright to cast a judgemental eye on its characters, especially the convicts, who are shown to mostly just be people who went through struggles. Some of them aren't even that, they're ones who clearly made their own beds but the show still doesn't judge them.
Also, Healy is an absolute piece of shit. He's worse even than Mendez because he doesn't even know that he's a piece of shit. And the one legged guy might be even worse.
I feel like the fourth season was quite a bit weaker than the other ones though. I also felt the final episode was quite a non-starter and very heavy-handed.