I've been to a lot. I'm lucky to live in the second largest consumer of manga in the world so they're very common. There are 3 long running manga/otaku cons (one largescale at 30000+ visitors over their operating weekend) in my city alone annually, and I'm not in the capital.
I used to go as a wide-eyed manga-lover and spent all my pocket money there, to the point I would usually save up throughout the year. It was my dream as a little kid to be par of one of them as an artist, and I actually did that back in 2021 
Since then I've only really gone to cons as an artist, it's really a different vibe and I don't think I can go back to "just visiting" anymore... At least not for now. I also know I prefer smaller cons, they're very hit and miss but the good small cons are really quaint and have much more of a friendly vibe.
I've actually got a con happening on my birthday this weekend, so I'll get to have an unofficial birthday party surrounded by people I love and random strangers coming and complimenting my work and giving me money for it, I couldn't wish for a better day 