Just started playing it today and I'm having a blast! There's a few things to get used to, like no movement on unroaded mountains or jungles but it's more realistic. Playing as Persia, it's nice to have natural barriers from the tougher barbarians and enemy civs, with all the mountains around, even if it isn't ideal for my cities. The pace is definitely slower, but I like it better. I get to savor the ancient age, as it's my favorite era. Haven't played beyond that yet.