This app used to be quite good. Now, it is simply garbage. It prompts me to login in order to use it. I do. And then it prompts me to log in again. And again, and again, and again. It never actually does its job.

This add-on was once great! But now the sign-in button just takes me to my dashboard and does nothing else. I don't use Firefox for much of my writing, anyway.

Doesn't worn on Firefox.

Works for basic spelling and punctuation; not so good at advanced grammatical constructs--given that "grammar" is most of its name, that's a problem.