I say 'might be' because it's not perfect. One of the main problems I have with this thing is that it doesn't account for things like voice. Sure, it may be correct English to never end a sentence with a preposition, but "The former was a problem I didn’t know if I’d ever get over." and "The former was a problem over which I didn't know I'd ever get." aren't the same. Ack, if Jo actually talked like that, I'd shoot her myself.
The idea with EditMinion - and other tool you use to edit, including other actual humans - is that the things being pointed out should only be taken as suggestions. Of course, you still shouldn't dismiss them outright. Take each one and evaluate whether it flows with your story. If you can reword the flaw and make your story better, great. If not, toss it on the trash heap. (Although, if the idea came from a real human, you might want to thank them for their time first and treat their idea with more decorum than 'on a trash heap'.)
In the end, though, I think EditMinion is a wonderful tool. It catches all my stupid 'passive voice' sentences, it reminds me that I'm using too many adverbs (again), and it generally talks my text out of context so I can more easily see where I fugged up.
Have you ever used EditMinion? How'd it work out for you? Lemme tell ya, the first time I edited and see all the pretty colors pointing out flaws, it was daunting, but I stuck with it. And I'm glad I did.