All three are quite different, which actually makes following their respective growth more interesting to me.
I suppose it’s fair that Tildes is not truly “competing” since they’re invite-only. I don’t have an account there but I’ve heard they want to focus on long-form high effort posts, so it’s never going to be real competition on terms of size, though it will be interesting to see whether a site with that profile can grow enough to thrive.
I’m not a fan of Squabbles personally but some people obviously are since they’re at 30k users soon. It’s run by a single person, and I am a little worried about whether that persons individual preferences influence development too much and in general the way development is heading. I don’t like the layout and I think the logo and name are a hindrance in terms of mass adoption.
On a larger scale though, Squabbles doesn’t allow any NSFW, and that is the benchmark I’m most interested in. Can a site of this nature reach critical mass without it?