It's a perfect grammar checker, even though it doesn't log in properly sometimes.

Good

It doesn't work in google docs like in chrome.

Great add-on. The only thing that would make it perfect was that it worked on more areas (e.g, Google Docs) and had more features moved from premium to regular (e.g, plagiarism).

Excellent product.... Though has some issues in some Facebook areas, like not showing when replying to a comment

I am really really annoyed by the intrusive ads depicting "happy students" and other left-wing nonsense shouting at me from Every media that I use. Besides, Grammarly is a YAS (Yet Another Spellchecker) only with hype. There are plenty of other hype-free spellcheckers available for Firefox and I will choose one that doesn't annoy me rather than one that I can not relate to At All and one that doesn't bring any novel functionality to the table!!!! If I were on an uninhabited island and Grammarly was the last ever available spell checker, I'd rather go without any spellchecker than touch Grammarly with a barge-pole (even if it's a very long barge pole)!!!! I find Grammarly totally useless and unnecessary... I think I've made myself clear enough?

Makes you make less typos. Handy app when free but can bug you to update.....

Many features only in Pro version.