Converso seems to blow all of these away judging by their features (check link below and scroll down to their comparison with other apps).

Here's a link: https://conversoapp.com/

I don't have a use for these apps so DYOR, but this one appears good because of certain features, like being able to delete a sent message on the recipient's phone, so signup info required, messages are deleted on their servers as soon as its sent (or so they claim. Again, DYOR), and a lot more.