I’m still exploring but I love frequency 2. While not a plugin, I also love the channel strip for every track.
Least favorite so far would maybe be the compressor. It is not bad at all and does what it needs but kind of meat and potatoes. I prefer my Black Rooster compressor or something with more color than this.
Least favorite:
Metalizer - whenever I use it, it just doesn’t work for me. That said it is probably just a question of preference. No issue with the UI or sound quality.
Most favorite:
Reverence (But watch out, I just bought Pro R 2 and holy shit this thing is neat)