As a guy that ran a network, I wouldn't join any.
To understand this, lets look at how YouTube advertising works and where the money comes from.
There are two types of advert:
1. Premium Ads: These are higher paying adverts that the network has sold for itself. CPM's can be $100's at times, maybe 4 figures in super special cases. The network can put these adverts on just your channel or broadcast them across the entire network.
2. Filler Ads: This is the typical $1-$3 CPM adverts sold on Google adsense, these only run when premium ads are not active or there are none.
I was dropped as a network because we were caught charging people $100 to be partners and giving away a 90% revenue share to the users, we never sold any premium adverts and had no plans to. Typical networks will offer you a 60% revenue share... but keep in mind they have fucking massive advertising teams who go out and find these $10 CPM's... but even if they do, bear in mind they do not need to give these adverts to you and they have no reason to...
Unless you have 250,000 subs you are a small channel by todays standards. The big channels bring the money in, they are the 'attraction' used by the guys selling the adverts to get companies to give them cash to make it all work and also, these are the guys bringing in the millions of views the network needs to keep going.
They have no interest in giving the cash to the smaller channels, they can leave and go join another network. It would make very little difference. They do not give a fuck about the $1000 a month you may bring in, the only reason they sign smaller channels is to stop other networks signing them if they go viral.
So if you want my advice, don't do it. You are going to get a shit deal, you are only going to get filler ads (which you would get through adsense anyway) and if you ever do go viral and get a million subs you will be stuck on a shit 60% rev share and you will be struck in a contract with no rights to negotiate.
It will only end badly for you, there is just no point in becoming a partner at this stage unless you are big enough to get a good deal.