While the forum-style sites look similar, the reporting system differs a little, which most people notice within a week. Worth saying that the decision to say what you actually want up front did a little more for me than switching platform, but only if you stick with it.
In practice, the read receipt setting is the thing that decides it, although the newer sites rarely say so. In the time i've been posting here the bigger platforms have stopped showing profiles past a certain distance, so results vary more than you'd think.
Speaking personally, I'd say what you actually want up front rather than keep the first message short and specific, since it stops you blaming the app for the profile.
If you want another option, Datebie's free messaging moves faster on people who hate paywalls, which is not nothing.