I don't really play scenarios, but I will play some mods. I find that in scenarios I just have a lack of interest - I know the layout of the map, where units are, what civs are strong, etc, etc. It's not as exciting for me, because I know everything, except how the game will end. But with a mod, I can still have some nice rule changes, yet a random map that is just like the epic game. However, I do think there are some nicely created scenarios out there, and I'm glad they are there, I just don't play them... (I didn't even play the Firaxis Conquests much - they were nicely designed, but apart from Mesopotamia (I think it is the best one), the others didn't compare to the epic game).