I post on SH, WN and FF.net(and patreon I guess though that feels different). However SH is my favourite one. I started out at WN, but not really a fan of the company, the way they do business, and their censorship. So I started looking for alternatives and ended up choosing SH.
FF.net is a mess with terrible search, discoverability, commenting functionality is terrible, and things break regularly. Also is meant for fanfiction which isn't all I write.
Wattpad doesn't have the kind of audience that would prefer my stories and also seems kind of a mess with similar issues I mentioned for FF.net on top of that.
RR denied all my novels so don't even have experience how their website is from an author's perspective.
As for SH itself. The author interface is pretty good, front page is pretty good and not ridiculously cluttered, comments work well, supportive of alternative income streams rather than trying to milk their authors and readers, pretty good discoverability and tagging. Makes at least a decent amount of the information regarding views available to the author.