Can't really talk about Webtoons since I do novels, but Tapas is alright. As far as novel posting goes, I do prefer it to all other platforms, but it still has a lot of problems. The main reason why I prefer is has to do with a kinder, more mature audience and the fact that Tapas blessedly does not do ratings (seriously, what are other novel platforms thinking by having ratings? Any schmo who hasn't even read your story can come by and give it 1 star).
I think my biggest problem with Tapas lately is that there seems to have been an algorithm change where your story is basically invisible if it happens to be fantasy or romance and does not have a big audience. I think it gets swallowed up by bigger stories that get a crap-ton likes more than yours does whereas before it doesn't?
Tapas also blatantly features popular stories far more than it used to. Like... Staff-picks (which they appropriately changed to "Novels we love, curated weekly") used to just feature up-and-coming authors, now they just seem to rotate between novels that are super-popular and ones that are premium (with maybe one or two novels that are new/have small audiences). I'm pretty sure I've seen the same novels being featured for 3 rotations. I actually preferred it when they had a popular novels section at the top of the page and had a staff-picks for novels near the bottom so that they could feature smaller stories without hurting their bottom line. shrugs