It's okay, but I have a bug where it doesn't check commas and punctuation.

And also on some form fields (like this review) it just doesn't work at all.

Mein schreiben wird seit einiger Zeit nicht mehr korrigiert.

Until recently, it was really great, but since the last update, it's become quite annoying. Every time there's a suggestion for correction, two windows pop up simultaneously, which you always have to close with a mouse click, and that's killing my nervs. If you, like me, use a lot of specialized terminology that the language tool doesn't recognize yet, the entire text is constantly plastered with suggestions. It makes working impossible. Additionally, it now only wants to correct into Dutch, even though German and English are selected. This renders the tool completely unusable.