Im a current premium user, and Im very disappointed with Grammarly.
My primary computer is a Mac, where I use MS-Word, Slack (web), WhatsApp (web), and Google Docs. *NONE* of them are supported by Grammarly! The suggested alternative on their website is using the Grammarlys Editor. Seriously?
I cant ask for a refund because the trial period is expired. However, I wont renew my license.
So, dont make the same mistake I did by just assuming that Grammarly will support all major applications and Operating Systems. If you want to use it, dig a little bit more about the Cons before you decide if its the right tool for you.
Good luck!