I have shot them all and out of the box you will be hard to beat a Steyr SBS or SSG in the factory catagory. I have seen them shoot with some of the best custom rifles as well. Steyr is at its best when reloaded. Its long mag gives the shooter a better overall length with the long bullets. At one time would have agreed it was a Remington.
I would have to vote for CZ. I have seen more of their guns "shoot" right out of the box than any others. I have a 527 Varmint with the kevlar stock in 204 ruger that is ridiculous. Can't beat the price of their stuff either.
CZ shoots well no dought, but I am going to throw one of the little guys out there and say Savage. Mine will do pretty darn well with some hand loaded stuff. Not bad for being on the low end of the money scale.
I don't know about the other rifles but took my Savage 10 GXP3 to the 100 yrd range for the first time Saturday and am extremely pleased with it. Shot it with only a bag under the forearm, nothing under the toe of the stock and the group is easily covered with a quarter. It likes the factory ammo I've tried. Both American Eagle and Ultramax. I'm trying to post a pic of the target and I know the gun is capable of better if I don't pull a shot. http://i146.photobucket.com/albums/r276/toxophilus/Savagetarget.jpg
I would also go with the Steyr. As far as a factory rig, they win hands down. I have shot most of them, and I wouldn't begin to compare a Savage with a Steyr. I can make a comparison with Savage and a Tikka or Sako, MAYBE a Browning.