I agree with a lot of what has been said above. Honestly, I've been liking LINE Webtoon more than Tapastic. Since I've posted my comic (shameless plug) on both sites on the same day in December, LINE Webtoon has reached 2.2k views and garnered 300 subscribers (just reached that number today, actually ^^), and Tapastic has only reached 600+ views and 35 subs, after a lot of advertising and some participation in the forums. I guess, because of that—the difference in readership—I have been more pleased with LINE Webtoon. However, with the new tipping program in the Tapas app, I hope to maybe turn the tides? At least in regards to revenue.
In regards to LINE Webtoon's rating system, I didn't like it at first, but that's because I tried to join the site originally during the first contest, where the site was first introduced to English-speakers. I had little to no readership then, and very few followers on any social media site, so I pretty much went in there as a nobody. It was/is also my first comic, so I was/am very inexperienced, and at the time, my artwork wasn't as good as it is now. And due to the competitive nature if the contest, my comic's ratings shot down to below a 3/10. That honestly destroyed my self-esteem for a while, and I ended up pulling my comic off the site (and never posted it here either). After two and a half years, I finally started posting my comic again, after many revisions and redraws and character redesigns.
Anyway, I imagine that some of the reason my comic is doing okay now is because I didn't join during a contest, so my ratings are pretty stable at 8.96 atm. I think the main reason that readership grows so quickly on LINE Webtoon is because they show the newest updates first on the Discover page, whereas, Tapastic mainly focuses on comics with a decent following already, trending comics, and other popular comics somehow (as has already been mentioned).