A campaign or a scenario is as best as the player are. I have tending to think that it's the Player and Master who is the more important. But, The Ennemy Within for Warhammer is amazing, as is The Great Pendragon Campaign for... Pendragon. I have personnally really enjoy Mastering Cloudlords of Tanara, and I found The Iron Wind really good, packed as it is with so much amazing stuff like plans, setting and beautiful maps. Eidolon, citie in the sky is a fun setting.