Perfect!

If you like all the text you write sent to advertisers and shady third parties.

Just take a look at their privacy policy, easily the creepiest extension I've come across so far.

Can't understand how it's still in the "Recommended" section. Mozilla WTAF.

I was not able to select British English, as used in Canada. Many different spellings.

Very slow to correct spelling and adds a lot of latency when writing.

Module complétement ridicule, ne connait même pas l'orthographe française, et quand on essaye d'utiliser la prétendue "intelligence artificielle" on obtient des phrases complètement tordues qui ne veulent rien dire. Parfaitement à l'image de tout système "d'intelligence artificielle", écrit des contre-sens, ne respecte pas les règles grammaticales, nul ! A éviter à tout prix.

Перестало работать

Problème depuis peu de copier coller dans firefox si je désactive l’extension je peu a nouveau faire du CC

ok

"This text is a little long
Upgrade to Premium and get advanced grammar as well as style suggestions for long texts."
No, I don't think I will. Other grammar checkers, can digest more and tell you their free limit outright

Not very good and over-complicatef

I meant complicated of course but this rubbish app didn't pot th error

If I can't install a different spell-checker on Firefox I'm going to use a different browser, that will be a shame.

Edited to add: Despite the Developer's response my opinion stands that this add-on is useless. Fortunately I have found an alternative that works perfectly.

The extension is no longer open source.

Некорректно определяет исходный язык.

A free spell checker now charges for spell checking! They highlight misspelled words, but you'll have to go to a search engine to find the correct spelling yourself; no, I'll find another spell checker!

NOTE:
The developer responded, "That's not true." I know my experience, but the popup bubble always says Basic Account and offers no corrections! Every single time, I had to go to duckduckgo.com to find the correct spelling. If Language Tool has decided to back off it's irritating policy, I don't know because I'm no longer using them.

A closed-source extension that is asking for access to all my data from all websites is a privacy nightmare. It's also a huge disappointment, as the add-on used to be open-source.

Не всегда правильно подставляет запятые

It does not work with the Bulgarian language. It recognizes it as Russian. You have an option for Bulgarian but it does not work.

No clear instructions for adding this add on to a android Firefox browser. Can't do a thing with it.