Rarely will an MCN protect creators. When you read your contract, it will have absolutely no language stating that the network will provide legal advice, defend you with Content ID claims, or any other protections. The agreement states that the creator gives them permission to monetize the channel.
Rarely do channels get sponsorships. The vast majority of channels in networks never see such benefits.
"Help with collaboration". This is an interesting point because many networks have forms for users to interact. Well, it's free here at YTTalk. =)
Rarely do networks provide 'great opportunities'. To be honest, those are usually given to the largest channels in the network.
Premium ads. Most networks just allow Adsense ads to be presented. That means that they don't have to do any work but they still get a cut of your earnings. Even if you did get a premium ad, it won't make up for the earnings that you are surrendering.
Finally. MCN's are not bad. It is important to understand what they can provide. If you are a smaller YouTuber, they may have dashboards or community forums. They often have music that you can use in your videos. However, all of these features can be found without being in a network.
The reason that some bigger channels are with networks is because THEY get the perks. Not you.
