I have been testing Grammerly as one of the tools for proofing and it is a definite help. Actually, a really good help. It is definitely NOT a "submit book and receive perfectly edited text in return." Far from it.

But, it will find many hard-to-see-by-the-author errors and the continual referencing back and forth from the text column to the suggested error lists somehow makes the mind reset and see problems that it would overlook in just a straight reading.

Often I disagree with the findings, but at least I see them.

And, of course, it chokes on the deliberately misspelled "flavor" words, but that is no problem.

I have run all three books though it and found hundreds of errors and suggestions, then gave one to a real editor and she found only a few left. So it did a really good job - far better than my self-editing by reading.

It is definitely worth the money - at least for me.