I consider my phone devices mostly read only. I do have an iPad and text editing is better, but still there are still stumbling blocks. Entering text is pretty easy, and making large scale cut/copy/paste edits is OK. It's the smaller edits, adding or changing punctuation, fixing typos, transposing words, or changing small words (‘the’ to ‘a’, for example), where I find difficulty with the behavior of the selection function.