As others have said the choice is yours. If you don't post here where else would you be able to build your following? You mentioned Tumblr, and I agree it is hard to gain a following there.
By posting on Tapas, it is free and there is a built in base of readers who can easily follow and read your work, but you don't have much control over the presentation of your comic, there is no ability to police comments, it can be hard to build a readership, you can earn money right away, it has a mobile app.
For Tumblr, you can have a custom URL and can install different themes that fit your content better, sharing your work is easy, setting up commenting can be awkward, as well as interacting with readers.
Webtoons has the advantages of Tapas, but there is very little you can do to interact with others, you can't even see who is following you, the series page is bare bones, and there are no forums, there is also a higher level you have to achieve to earn revenue. It seems pretty easy to gain subscribers there.
Self-hosting is an option with a custom domain, but it costs money and you have to set it all up yourself, but you have the most control and freedom, you don't have to worry about weird Terms of Service, or the site going under, but it is harder to build an audience, and it can be hard for readers to follow since they have to use bookmarks or an RSS app to keep informed about updates.
I would say, think about your options, what your goals are, your technical skills, what you like as a reader, learn more about the various sites available to you, and ask the community questions. If that means you don't ever post here, post here exclusively, or use the site as a mirror, then you can do so confidently.