I installed Babble on a test forum.
Some users (including me) report having problems with scrolling and typing. I don’t know (yet) what device they used. If you need that information, I’ll ask them.
When using chrome on Android 6 with a 960 x 540 size screen, I have trouble finding the text field. The messages have their own scroll area and when I drag there I obviously can’t reach the text field. I need some more tapping here and there to reach it.
Next, when I want to type my message, the keyboard (using Fleksy) covers the text field, so I can’t see what I type.
Other than that everyone loves it so far, expecially that it is accessible everywhere from the header.