For what I can see, Invoke is just a revamped version of Fabric’s task running components.
Fabric 2.0 will "leverage Invoke for task running, leaving Fabric itself much more library oriented".
I am aware of that, but I still consider it one of my favorite libraries, and thought it would be useful to mention that it's not yet py3k-ready. I can imagine quite a few people might depend on it. What are you using instead?