I don't like labels in general, but I've been thinking of claiming "Must-ISH-ian". I downsized my house by 40%, cut cable, don't eat out much, eat $1 work lunches that I cook in bulk, spend very little on clothes, got Republic Wireless, and drive very conservatively... but I have a car loan and a CC balance (at 0%, but still, right?). I still eat out a couple of times a month, while that 2.25% APR on the car steals a dollar from me every day! Oh no! Facepunch!
I've picked up a lot of MMM habits but plenty of anti-Mustachianism remains, some of which I may not give up, but most of which is just a matter of time. It takes time and attention to methodically remove waste and unfulfilling habits, even if you know they're there. Maybe later when I've streamlined the majority of the known "exploding volcano" shit, I'll say I'm Mustachian. It's not about SR per se, I base it on having done what I can to optimize my pursuit of happiness as opposed to just living by habit and groupthink.