I began posting to the now all but defunct ASSTR about 20 years ago. I started posting on SOL in 2003 and LIT sometime after that. When I discovered Lush about a year ago, I decided to try it. Each site has its pluses and minuses.
I don't care about scoring and, although nice, comments aren't why I write. I write because I enjoy it.
Because I tend to write long stories, I find SOL works well for me. The site allows you to access multi-chapter stories from a single pane of glass. The turn around time is usually quick.
While I like Lush, I find not being able to post stories/chapters over 10K words frustrating. I have discovered many readers here prefer short stories, rather than novel-length tales. That said, I do like the community aspect of Lush. I have enjoyed the offerings of many very good writers and will continue to post and read here.
As for LIT, I can take it or leave it. As I said, all the sites have pluses and minuses.
As a writer, I feel it's important to know your audience and your venue. My long tales seem best received on SOL.
Rookie Scribe