Well, this is a battle that has been going on for ages: Tapas or Webtoon?
In my personal experience I'd say Tapas, mainly because it has more tools for creators and offers you the possibility to interact with your audience and other creators (the wall and the forums). You can also rearrange episodes after you posted them, which is not possible on Webtoon. Now, they did implement some features (very recent features) that I didn't like, for example they removed the bell icon and completely changed the inbox. I also very much agree on the fact that they're pushing out premium comics a lot more, which I find quite annoying (as you can see with the new inbox).
Webtoon, on the other hand, is not that creator friendly. It's missing lots basic features like notifications for likes and comments, so if you want to check for them you'll have to click each episode manually. Many things that Tapas already had were also included much later on like the possibility to schedule an episode. The creator's wall and profile is also a relatively recent thing they added and it's quite bad since they should've done it much earlier. Also it doesn't help that you can only edit your profile through the app, which is a shame. Overall, I don't think WT is that great of a platform, at least from an author's pov.
However, I still think one of the best platforms for self-publishing out there is GlobalComix, due to its very creator-friendly approach. I like it a looot more