Other than here on Tap I post on Comicfury, which is my "main site", and I love it! It's just a really great host for all kinds of webcomics, and complete freedom over your layout and site + adding extra pages is a big plus for me. CF is love, CF is life x3 Highly recommend, and probably your best bet for your "own" fully customizable site if you don't want to buy your own domain (one of the main draws for me)
I started posting on tumblr when I first made the comic years back but I quickly got sick of having to cut up comics into several images to avoid resizing and decided after a while I wanted a "proper" webcomic host anyway. Plus never got much popularity there, even with a sorta-fancomic (though one cool thing that happened is that one of my comics got liked by Shiftylook, Namco's official (now defunct) webcomics site - pretty proud of that)
Also post on deviantart but mostly because I post all my art there anyway haha x3 Got a few new readers there, so that's cool
As for Tapastic... it's alright. Got me a few more readers but the sub numbers and views on here and CF have stayed pretty consistently similar so it doesn't seem to have given me much more traffic or bigger audience compared to CF (plus CF, being my main, is usually the site I link to elsewhere) Honestly not a fan of how you can't customize your own site's look or even add extra pages... gives my site less of its own personailty, and having extra pages at least would be handy for creators who want stuff like cast pages, various info ect. I get a "standard" layout can be convenient for readers but still...
Never tried Smackjeeves, Drunkduck/The Duck or Genesis but after CF I don't really feel much need to, and 3 sites are enough to keep up with at this point. Haven't tried webtoons either but from what I hear about their size limits I'd have to cut up most of my comic images into several images and i'm NOT going through that again, that's the main reason I stopped posting to tumblr.