An excellent tool with a lot of grammar, sentence structure and style tips as well!
The reason why I gave it a 4/5 was because I type Dutch and German a lot and this add-on has limited support for compound nouns in these languages. (although it does support them far better than the browser's spellchecker does by itself)

very bad performance. high cpu usage even on static page background tabs with addon enabled

addon itself is useful

Great addon - only the blue checkmarks right of pretty much every paragraph of text are kind of annoying and clutter the writing process.

parece muy simple pero ayuda porque somos dados a escribir por escribir y nos ayuda a coregir

passt

Très bien, mais la version premium est trop chère

Solid grammar and spelling checker. Not quite as effective as Grammarly, but certainly more secure.

It has a Grammarly feel to it

I would say that it's a really good app and I'm going to keep it. I just would think it helpful if you make it a bit more accurate. But it's very useful in my opinion.