Is Grammarly premium worth it?

If you have Microsoft Word, just use the built in spell and grammer check. It's far more capable these days and is very feature rich.
Another user pointed out how much worse you can make your writing using it. I had a peer in a group project put our work through Grammerly and mindlessly accept what it said to do and it ruined the writing.

Mind you, I've never been a fan of Grammerly and certainly don't understand how people could pay for it. And certainly would never be comfortable using it for free, because then they're data mining me.