I wasn't going to bother watching it as audience and critic reviews were so bad. however, my son wanted to so I begrudgingly went. It wasn't as bad as I was expecting, but that doesn't mean it was good.
The original Joker film was okay but not good enough to add it to my ever expanding bluray collection. My main criticism of that film was that it was a decent story about a man going insane and killing people, but the Joker content was thrown in to sell tickets. Even though this film has a version of Harley Quinn, I still felt the same.
So take the Joker aspect away and it was a decent continuation of the first film. Joker showed the audience that they were watching what was going on in Arthur's mind, not actual reality. This continued in Joker 2 and I thought it was an interesting take on someone with severe mental health problems. The presentation that it was a "musical" illustrates this quite well. Arthur is in full fantasy mode.
In summary, the 3 star score reflects that it wasn't bad, but wasn't good either.
I have to say the amount of smoking in film really irritated me, but that's a me problem I suppose.
And finally, I wasn't expecting the ending. Not sure whether that was a good thing or not.