Vox (the new service from the same company): Not so much.
It seems to me that Six Apart, who accepted a lot of funding for making Vox, have made it inferior... deliberately.
It may very well be better than MySpace, but it's clearly designed to compete by being yet another user lock-in service. A shame, but it's to be expected really. And to be fair, nearly everyone does it. Flickr is no better. (Flickr competitor Zooomr allows OpenID login.) Although technically you could use the Flickr API to get your data if you want to break free. Just as Flickr, MySpace, YouTube and others are doing, Vox is trying to be an appealing service that no one wants to leave... but failing that, will settle for being a service that is difficult to leave.