What is open for all vs open for some will always come down to the definition of the word "open".
If we are talking about open as in permission to use, modify and distribute, then both licenses are equally "open".
If we are talking about open as in permission to close down the permission for others to modify or distribute newer version, and sue anyone who acts different - Then we do have one license that is more "open".
One could also argue that a standard business model of today rely on being able to threaten users with lawsuit if they modify or share the software. The "openness" to use such model is only available for one kind of licenses and not by others.
I might not go as far as calling it more open, but then I have a distinct opinion on the word open.
Aw, geez, and here I tried to avoid these debates. I used "open" to try and imply that GNU's license will keep the source code "in the open", as "open" implies something different from "free". I'm not going to argue that one is better than another, or that one gives more rights to derivative users or not. That way lies politics and madness :)
GPL is only open to users who have a developer willing to distribute the code in a workable form. Given the GPL is often used in the "pay us if you want to ship" mode, I don't see much to recommend it versus BSD. GPL can die just as easily as BSD without developer support.
