I also started on Marble Hornets. It was referred to me by a few friends from the interwebs. I stayed pretty close to that before finding Tribe Twelve, then Everyman Hybrid. I only recently (within the last few weeks) started really watching TT and EMH. Anyway topic:
I really like how they did this crossover. One thing I have a problem with is they're this far along, and they still kind of dodge around Slendy. They never really talk about it. All they talk about is, "Yeah, some bro keeps sendin' me crap and stuff." Or maybe I just haven't watched any videos where they have?