Ok, I'm changing my review. I've been testing the addon, and for most of the time it works. Sometimes it doesn't but I suspect it may be an issue of YouTube. It doesn't work with playlists - instead of hiding them it says the playlist was saved.

Frequently I need to click 2 times to make it workind and/or close a window that pops up in the corner.

24 days passed still not working :( .....EDIT: working again..thank you :)

Thank you! It's almost perfect. It doesn't make sense to me that the buttons are visible in my subscription feed. And I'm missing a Hide this video button to keep the feed clean. Cheers!

Works as expected. I would prefer not to have the "do not recommend channel" icon along with the do not recommend, so I used uBlock to hide it. Other than that this is an extension I now use in all browsers.