Didn't work at all...

Badly-written 36 MB addon which stops working after it is disabled and re-enabled, requiring reinstall. The company has very aggressive marketing and forces people to install this addon. In contrast, Linguix grammar checker works online without any addon. This addon integrates everywhere, thus sending anything what is typed to Grammarly. They don't care if it contains sensitive info.

Once you turn it off? You have to re-install it to turn it back on

causes fire fox to crash

not correcting properly

It used to work on my Auctiva page but all of a sudden stopped working a few days ago. I re-installed - still not working. Still works on my Yahoo mail, but not on Auctiva.

Grammarly is not appearing in Firefox despite my carefully following the directions. It used to work well, but I cannot access Grammarly now.

when I copied rom gmail and pasted to my facebook, it seems that parts of the text were recopied or corrupted.

Very Slow, no local chaching. Often updates and insets the corrected word into the wrong part of the text box.

Grammarly performs very poorly.

For instance, according to Grammarly the following nonsense has:
- Correctness: Looks good
- Clarity: Very clear
- Engagement: Very engaging
- Delivery: Just right

"These could simple and straight flat blue. Yet not tomorrow rain future but today yes maybe or might, even yes, sun, cloud, TV or desk. With this no black and red, yellow blue with green, sunshine with no and yes."

Horribly privacy policy.

It starts to block/interrupt typing Korean while I am writing message on Facebook. I had to disable it.

This add-on would be useful for many people but on Firefox it just isn't usable. With Grammarly activated Firefox CPU usages goes through the roof on my Macbook. My Windows PC is bareable because it's a powerful machine, but on a slower work provided PC Grammarly is just too slow. I suspect Firefox's API just isn't providing the needed functions for Grammarly to work smoothly, but unfortunately this goes against the extension itself.

I don't need Grammarly because I have auto-correction

Grammarly sends up to 10k DNS requests to it's servers every day. That's 380 requests per hour! or 6.3 requests per minute! Queries servers are grammarly.io, grammarly.com, grammarlyaws.com.
Why would they do that?? Why would grammarly addon ask for IP of mothership server so often? Uninstalling this.

It is wrong more often than correct. It works halfway decent on spelling, but grammar is wrong most of the time.