Ok, this it the last seed of 4.1 to developers. I'm guessing they have already signed it because you don't need a dev account to activate. If you know how the shift click works and don't mind downloading a torrent. You can't really go wrong upgrading early. I'll try later tonight...& report back.
That's exactly whwt i did yesterday, everything works, from HDR photos to Game Center, the only thing is there are no games updated to work with Game center yet