After having looked at each of these two projects, it seems that both are VERY similar. Both run on top of the CLI, both have python style syntax, both use .NET instead of the standard python libraries.
So, what are the differences between them and advantages of each?
I agree with VolkA here. Being able to run Django is big. It's just such an amazing framework, that Boo will have a hard time redoing it. Today it's more a question of the frameworks that a language provides, than it is the construct that it provides. And Boo doesn't provide much improvements over Python in the constructs it support.
Boo vs. IronPython