That's not what I said obviously if you are jb on 4.0 or 4.0.1 you are going to gain features by upgrading and jb at 4.1. I was saying if you are already at 4.1 jb with Limerain there is no need to rejailbreak with greenpoison as you will not gain anything.
Ah....that wasn't clear when I first read your post. Now that I understand the context, yes, what you wrote makes more sense. But, there may be issues with Limera1n that Greenpois0n may not have. This is one of the reasons why I am waiting for a while before I upgrade to iOS 4.1.
S-