I had to use it for a class. I have some vision, and I didn't find it extremely hard to use. It might be harder for someone with less vision than me though. The selection tool to highlight what you want to annotate can be really touchy, which I think is an issue with the program itself. I liked the collab features, but I can't remember how accessible it was. I know they had accessibility features, but I don't know if that was just zoom or if it offered text to speech options.

If you have any specific questions, I'll do my best to answer them.