To the tune of what others have said, it's been good and bad.
I never went through the over-identification problems or let it affect my day-to-day life. I probably had some pretty dumb opinions until I got a better grip on the complexities of the theory (cognitive functions, etc.). In fact, I know I did - I remember having the "N is superior to S!" phase because I thought it meant the difference between someone who enjoyed discussing deep, juicy abstractions and someone whose idea of conversation meant reciting their grocery list. So that was pretty pathetic while it lasted.
In terms of big-picture negative drawbacks, there really haven't been any. I'd say my biggest issues have happened within the community itself, specifically online. I'm here because I find typology interesting and I believe it's a tool best used somewhat loosely. When people ardently stick to a "No, this is impossible, because the rules clearly state X, Y, and Z!" perspective, then I kind of check out because my logic isn't as black and white as that, and I find that approach to be too limiting.
In particular, I'm not a fan of the idea that Enneagram and MBTI must fit like a glove. They're two different systems with yes, likely a lot of coincidental overlap, but I believe in outliers even if they're hard to imagine at first.
When I realized that my Enneagram wasn't type 1 after all (and I updated it to the one I believe is definitely accurate), my INFJ tag became unthinkable and I wasted entirely too much time defending why I feel the way I (still) do to others. I've had so many back-and-forth exchanges wherein someone's like, "You sure you're a 7? You do come off as INFJ" and then when I describe why I'm a 7, it suddenly shifts to, "Oh, man, that's pretty textbook! So you can't be INFJ then." I'm fine with those thoughts if I'd get some kind of constructive feedback, maybe some reasoning that tops mine by teaching me something new, employing a line of logic that I haven't already considered - but every one of those exchanges has ended with the other person just sort of walking away from the subject. So I'd consider that a negative.
To an extent, I get it. It's an odd combo for sure, I just got tired of people telling me I'm wrong or that it's directly conflicting/impossible without really hearing me out. Or, you know, people straight up PMing me to say mocking things, like they can't decide if I'm joking, and if I'm not, whether I ought to be put in my place. It's been kind of an uphill battle to be taken seriously for community discourse, sometimes. I dunno. Seems like that defeats the purpose to me, and it's left a really bad taste in my mouth. It's one reason I never hang out here for very long.
(I'm not really attached to the INFJ label, it's just the closest MBTI type that fits my cognitive stacking, which I'm pretty sure just is what it is without me being "unhealthy." My solution has been to name my top functions instead of the four-letter combination, and I think that's better. Feels more accurate too, which I like.)
On the flip side, learning about the Enneagram and instinctual variants has been wildly helpful. All my life, I've felt like I've had some kind of existential fever. Reading about the sexual instinct (not the squishy, looking-for-a-soulmate descriptions - the unstoppable ache of the intensity junkie descriptions) was incredible, like finding acknowledgment that this fever exists, validation in feeling this way, and the ability to give it a name. That was huge. I might be an extreme, even for Sx-doms, so that felt enormously important.
I'd love to hear why they dislike MBTI.
