My friend group and I picked up Congregation for a one-shot after being familiar with ECB. What we liked most about it was the easy-to-put-together character sheet and the theory roll that told us how much we knew about the obstacle we were up against. Even though it was a one-shot there was definitely enough to keep us going for a series of sessions if we wanted to - we ended up with a loose end of an old lady who was responsible for summoning various demons, and if we pick it up again, I know for sure that one of the characters will be hot on her tail!