I had a young (pre-teen) boy who filed copyright claims on several of my tutorials, and they where taken down instantly and took months to resolve via email. I lost about $1500 in revenues which was never returned.
Beyond that, YouTube is taking a ~50% cut of your ad revenue AND any donation revenue on the site which seems pretty extreme. They also don't do good when it comes to new content discovery, as the YT search promotes mostly popular content (basically, bad for new creators).