I am interested in using Kami this year for my classroom as my students will have touch screen Chromebooks. I think PDF annotation will be something we use often to make things less paper based. I have been currently testing out Kami on my Samsung Chromebook Plus. I have noticed that the stylus support as well as finger touch support is not that great. I have been taking notes with an Android app on my Chromebook, and I get excellent response and nice hand writing with the stylus and finger. While my students won’t have the same device that I do, I am worried that they will get frustrated with their writing by finger or capacitive stylus.
I have always seen Kami as the number one Chrome extension for PDF editing, and it seems to have nice integration with Google Classroom.