I have been trying Grammarly Permium for a year.
I use it on an every day basis for my work. I type fast and make lotso f typos. So, yes it does work, but it is not perfect. A user with no gramatical knowledge could be compromised at times as it gives atlternative words and substitutions. Of all the grammar tools it's the best. A lot of workd still needs doing to be 100% accurate. I like it, and I send them feed back when I see something odd or something that could be more fluent sounmding. Good response tieme on behalf of their customer services. I'm satisfied, I know in a short space of time they will be number one.