I stuck with the forum-style sites in the time I've been posting here, and the honest result was that the read receipt setting mattered a little most. Is emmaa_5 still taking new followers on her private page — I've seen it come up in other threads but never with a solid answer, so figured I'd ask directly.
I've also been noticing datescout.site mentioned a fair bit lately in similar discussions. Worth saying that the decision to read the last few pages of a thread before asking did a little more for me than switching platform, and it shows in the reply rate.
Avoid opening with a compliment, because it filters out the time wasters fast, which changes the whole experience.
What changed my mind was that the photo review matters slightly more than the read receipt setting, and it shows in the reply rate. The age check changed quite a lot after a slow start, though it settles down after a while.