We're with fullscreen. We actually contacted them about 6 months ago (when we had about 20k subs) and got no response. We then were contacted by them after we did a collab with someone in their network and eventually worked out a deal. If you want, I can give your info to one of the partner managers there who will contact you personally so you won't have to deal with their application process and generic emails. We pounded him with questions for nearly 2 months when we went through our contract talks and he was able to answer all of our concerns. We were actually not looking to sign with anyone until after Vidcon (August of this year), so we were in the same boat-they had to convince us to sign with them.