For me, 12 dB/octave lets me shave signal with more precision. But user your ears and find out which you like best.
Proximity guides me low-end bump if I want it, as long as as I'm using Mic modeling. But that's a total use-your-ears thing.
A lot of people don't even try them.I agree let the ear tell you.... I too, have been using 12db and Proximity on..... it just sound better to me (I mostly use Marshall'ish type amps) ..... what I'm wonder is "WHY" do I prefer.... because I don't see a lot of people that share or sell their presets... use them???