I wanna weigh in on that with two comments:
1. I unsubscribe way more quickly from a channel if I have to watch an ad before each video. The content has to be really good for me to accept that. I would recommend you to wait with your monetization until you have a little bigger of an audience.
This, exactly.
I've set monetization for my videos (At least, a few of them, I think) and
I make sure to turn off the video ads and only have that small pop-up thing.
The video ads are extremely obnoxious, I'm tired of waiting a while for the ad to finish, sometimes it just really isn't worth it and I close the video before the ad finishes. Even worse, an ad recently put on YouTube would get stuck as soon as it reached the end (Where it says "Click to buy the album" - very fishy), so you've just spent 30 seconds watching a boring advert for a band you don't care about, only for it to get stuck...the reliability is horrible. That's not even the worst part; if you have a slow connection, you're going to be waiting for the ad to load...which is just pathetic and painful.
I'm never going to turn on video ads, I hate them, and I don't want people who are taking the time to watch my videos to get frustrated waiting around and then decide to not watch it. You can skip some ads, which is bearable, but I still don't want my viewers to have to wait for the skip button.
I'm fine with ads to make things free, I'm fine with the small pop-up ads on YouTube to allow the person to earn some money, but the video ads are just not good. If you don't have ads at all, I salute you, and I think
CaseyNeistat very rarely puts ads on his videos.