Very buggy it used to work OK but lately has not been useful at all, videos would start looping for no reason with autoplay enabled, quality settings are not working (at least not for low quality toggle), ended up having to delete it to get autoplay working properly and have now found 'Enhancer for YouTube' which seems to be working properly and it might be a little early to say this but so far it seems way better and I will not be installing this addon again