I am rarely affected by them at all. YT is very good at filtering out the spammers. I see some of them in my 'held for review' section, but simply delete them. Almost no spam comments get through to my comment section.
Some spammers use a well crafted comment, but if they include a link, I have YT block links. The ones trying to advertise their page in my comment section can get through the filters, but that takes work on their part, and most are too lazy to do the work, so I do not get very many. The automated stuff is usually handled automatically by YouTube.
I also get very few troll comments on my page because I have HUGE word filter to block most of them.