As a history teacher I often found myself pulling primary sources for students to read or reading work that my students turned in to me and while google classroom does have the ability to suggest edits and give feedback Kami provides a few more features that I have come to love.
First of all Kami works with PDF's as well as text documents and includes the ability to highlight, underline and draw on documents so as students are reading a text for class they can take notes or mark things they would like to talk about once the class pulls back together, and with Kami's integration in google classroom each student will be able to save their edits to their drive!
Kami also offers the ability to record audio or video feedback on a document. This is a very personal touch when it comes to leaving students feedback on a paper they wrote. I saw in my classroom that students were more likely to take my corrections when they saw that I had placed extra effort into giving them all individual feedback. On my end, recording a short video did not require a lot of time because I was able to articulate more accurately why I was suggesting a word change or other correction.
In class Kami gave me a surface that provided the students with a "teacher" copy of notes that I could easily upload to google classroom. In the event that a student was out of class or needed to check information before a test Kami provided a very effective way for me to capture a lesson.
Kami does have a paid version but the free standard does come with a lot of features and is well worth looking into if you use PDF's or google classroom in your school. This simple piece of software packs a punch in it's engagement potential with students and I have seen first hand how Kami enhanced student voice!