So I might be biased, especially so because I have had Buckeyes and not Marans.
Buckeyes are a lot of fun to have around, and produce pretty well. Males and Females both are very comfortable around people even when given little interaction. They do very well in both Summer and Winter. There are several programs setting up breeding for Buckeyes as it was a breed that was near its end not too long ago They do need a lot of work to dig out of the hole they were in. Marans are more of an up and coming breed in the US, and have a lot of interest right now due to this.
If you care about looks, nothing beats a Buckeye Cock. They have an interesting look about them, relaxed but alert at the same time. Commanding but confrontable. They show really well(in my opinion) due to this, they are a stand out bird with a lot of character.
-Link in signature if you want to find someone who can get you some stock, we also have a facebook group that is pretty active.