Terrible. it is a bait and switch scam.
It did not correct not even one thing that it claimed is an error, instead, it requested all the time to upgrade.

Barely works. Constantly ignores context, can't grapple with simple things like attaching links to words or casing for movie/video game titles. Often can't understand paragraphs that go off-page and wants to apply periods and capitalization to those words mid-sentence. Recommends pointless changes then creates 100 new errors based on its recommended changes.
Seriously, go to the store and buy a grammar book. These apps are so unreliable.

I couldn't even try it before it asked to login.

Broken - displays its own weird huge glitched logo in place of many forms preventing me from inputting text. Doesn't support Polish.

Is in actullity a free trial, it says nothing of this but after hellping to correct a few words stops and want's an upgrade.

Not working at all. Says: "connecting"

This Extension popped open windows in front of text I was trying to edit to terrorize and bully me into buying their pro version.
This kind of behavior should come with THE MOST EXTREME form of punishment.

Avoid this abusive behavior.
There is literally NOTHING this company can to "unring" this abuse for me.

I will be reaching out to every form of social media to the communities I am a part of to avoid these "terrorists" at all costs.

Your competition thanks you Linguix.

Suspicious behavior. After installing the extension, it opens an unlimited number of self-promoting tabs, in which there is a message asking for the installation of "Linguix for Firefox extension" already installed.

Very annoying reminders about buying suspension with questionable utility plugin