But, for a dutch oven, I think I'd go enamel. The point of cast iron is how hot you can get it and how well it holds heat, great for searing food, etc. That's all great for a pan (where I would recommend cast iron), but I don't see the value for a dutch oven where you are more often going to be cooking at a lower temperature or have a significant amount of oil to hold the heat. For that, it's just a nuisance that's harder to clean and the dark color makes it a little harder to see what's going on in there vs a light enamel.

One other note is that if you cook acidic foods, tomato sauce for instance, some say (others say it's insignificant) it will wear down the seasoning or introduce a metallic taste to the food; I've not had a problem with either, but throwing it out there if you are sensitive to that sort of thing.