I liked Joker. It was different in that there wasn't really all that much plot when it came right down to it. It was a deep dive into an individual and very well done.
Phoenix was great. I thought I'd be comparing him to Ledger but I can't really. Phoenix's Joker was about society and outside forces shaping him. Ledger's Joker was about a more evolved Joker having judged the society and manipulating it. The Joker writers did a great job. You could see Ledger's Joker arising from Phoenix's or not. They made it independent but not totally removed.
It's odd to me that a comic book villain could produce two of the better acting performances I can remember, but I thought Phoenix was great and years later the Ledger Joker still amazes me.