Both Grammarly and Ginger It are good for a newbie writer or for someone who is not confident with his or her English yet.
One thing I don't like about Grammarly is that it doesn't care about the writer's persona or style in writing. There are thoughts that are best delivered in a passive sentence but Grammarly makes it appear critical when the sentence is not in an active voice. Where's the danger in it? There are clients who are not confident with their English. When they see the word "critical issues" by Grammarly, they make it a big deal as if the world ends later at 3PM. Of course, it's a marketing trick for Grammarly to pick adjectives, like "critical", so that free accounts would be lured to become a premium Grammarly user to reveal those "critical issues".