When there was action, it was fairly top notch. I felt it was a little weaker than his showing in DD S2 and Punisher S1 though. He just rarely commanded the level of badass as he did in those. That's not to say it was bad, it just felt maybe a little generic, and at times, reserved. Curt and Amy may have had a part in that since they were always nagging him.
My biggest complaint is there was just too many story threads to have an enjoyable, gripping experience. When Pilgrim was given some solid screen time in the final 2-3 episodes, I finally was won over to enjoying him. Prior to that though, I really didn't like his character. He was one dimensional and didn't really help drive the overall story forward. Until those final episodes, I was really wishing he would of died in episode 3 during the police department fight and Amy got offloaded so that the plot could focus more on Frank and Billy.
Instead, we had a story between Frank and Curt, Frank and Madani, Frank and Amy, Frank and Russo, Madani and Russo, Russo and Krista, Madani and Krista, and the random jumps to Pilgrim and the rich parents. There were just too many threads it felt like, and while Amy and Pilgrim were cool by the end, between episode 4 and 9~ it was just a massive slog and I didn't enjoy it. Having characters not really develop and move on like Mahony as mentioned above, or Curt's constant "I want to end this - I don't want to do this" shuffle, it felt like there was a lot of wasted time where no progress was really made.
I really dug Russo up until maybe episode 8 or so, where he was confused and didn't know anything, why he was hated, what to do, etc. Once he more or less reverted to himself, I dunno. I felt like the move discarded something that was key to his character in S2. I really liked when he broke down after the robbery because Frank aimed a gun at him. Frank having enough of his bullshit in the final few scenes was a mixture of sadness and satisfaction.
tl;dr - I wish they had given us more Punisher and less offbeat story threads that interrupted the action and flow.