Quite a few pedals are quintessential, But when you factor in price range, history, and character, not many are in the Big Muff category. You could, of course, get a few bucks more and get one of the variants, but if you're not that interested in pedalboard real estate, or after the very specific sound and are just interested in the Big Muff fuzz sound, this is arguably the best option for you, save maybe for some DIY clones. It's currently being used for some fun Seattle-style grunge sounds, but it fits right at home with anything that you want to do with a wall-of-sound type tone, or some very interesting dark, jazzy melodic work when the guitar shouldn't sound entirely like a guitar (just the tiniest bit alien).
It is, though, very full of character, and you can always recognize a Muff style pedal from a mile away in most mixes. Never met anyone who actually didn't like the sound, but I'm sure you're out there. It does play very well with synths as well as electric guitar (been using it also on some melodies with my Korg Minilogue XD, and it makes it sound like a very peculiar guitar some of the time).
And, as a cherry on the cake, it's also a fun pedal to mod, which is why I got two of them. The big box makes it so you can fit almost anything inside it and it won't get really cramped. So if you're not totally convinced on the sound, but get intrigued by it's spirit, change stuff around! Swap in resistors, take away diodes, or even take away one of the gain stages. All in all, in my opinion you can never go wrong with this piece of history, and everyone should have one in their arsenal.