I spent the USD$59 for the VST yesterday and started using it on a new song (actually a re-record of a song that is so old that I did it on my Tascam 688 cassette based system and don’t have a copy of the mixdown in a format that I can play ).
I love it! It supports Bob Katz’ K system without having to use an SPL meter, which is why I bought it, but it also can generate automation based on the levels, MIDI CC data as well (for driving a lighting system, for example), etc.
It’s well worth the money, but now I have to go back and ensure that my previous songs are in the same loudness range for consistency’s sake. Ugh.