These: "Wow it's amazing" reviews make me wonder how legit they are. I find it hard to believe that everything is perfect and nothing could be improved at all. As for my experience:

-1 star for the extension being intuitive. it's not.
-1 star for: "This add-on is not actively monitored for security by Mozilla. Make sure you trust it before installing"
I'm not sure how you're supposed to be able o quickly research and monitor the security of an extension.
-1 for a dev who seems to insult his users instead of taking reviews as constructive criticism. (here's couple of his responses to previous reviews)

" Overall, you are here just defaming a legit work that I've been working on for years because you are a hater 🤷. Be better and do better."

"Hmm ok, I am sad to hear that. If you don't see any value on Ultraviner free tier compared to Amazon default interface you should really just keep using Amazon :)"

I plan to find something else to use or as he said: "keep using Amazon"

I didn't see much benefit to this plugin. After hiding items the pages still remain there, just blank. So you still have to go fishing through thousands of blank pages. Also after installing this, Vine kept having me login over and over every day. My password is tedious to type as it is secure. It would be great if it just showed remaining items instead of the thousands of blank pages. I guess one useful thing was the bug fix on looping items.