I do fine until I make a typo and have to re-position my cursor to correct it. It freezes at the point I position it and I have to close and re-open the keyboard to get it working again. I do not notice this behavior on other forums.
I did figure out a little trick: if you leave the editor in Standard mode you can type a bit more normally by tapping the HTML button.
Use a p surrounded by < and > to begin paragraphs and /p surrounded by < and > to end paragraphs. Once out of the HYML editor, the Post button doesn't always work for me. To get around this hit another button such as the Bold button, then Post.
Honestly, with the amount of employees and being by far the world's most expensive Bible study software - I hope this kind of thing will be fixed soon. :)