Their ads are terrible. And since I watch via a device like Roku, etc, I have to put up with them. I've actively removed them from my devices. Occasionally, I feel like looking up some video. I install it, and often before I even watch the video I uninstall it because the awful UI reminds me of all the other awful stuff in it.
Curation doesn't exist. I have to work hard to find good content. Harder than any video service out there.
And shorts. Oh. Dear. God.
For some very targeted stuff (home repairs, video game walkthroughs), it's great. For the rest, it just sucks.