Wattpad: You can post your work, but with 100M+ users on the platform you'll have to promote it elsewhere because no one's gonna notice it. We've closed the community forums and everything is up to you. No one cares. Bye!
Inkitt: We're reader powered and we have somewhat of a forum where you barely get any interaction at all. If your work isn't werewolf mafia CEO billionaire stalker dark extra extra spicy romance, no one would probably notice it. Or feature it.
Webnovel: Bring all your anime-inspired ideas here that's similar to all hyped shounen you've watched many a repetitive times. Don't mind the uncanny number of reads because they're inaccurate, as opposed to the actual number of people who've read your work.
Honeyfeed: Are you a real otaku with a heart for writing light, very light, novels? Share your Japanese-inspired works here and make sure you get the word out or no one will bother. Don't forget about truck-kun, kawaii-chan, and whatnot.
Anyway, app and web novel wise, I like that you can in-line comment in Wattpad, but hate that you get ads every page turn unless you're premium. I'd prefer Inkitt if they had an in-line commenting feature. I also prefer unconventional hidden gems that doesn't go with overused trends.