A friend of mine was just asking me this yesterday...I own a CZ 452, which is a very capable factory barreled action. I've shot a Savage MKII TR many times, which I feel is also a very capable factory barreled action. I personally have seen both shoot (and have shot) 1MOA or less at 100 yards with quality ammo.
Definitely look/search around on this forum and you will see several topics that cover both rifles. As said, one will not outshoot the other. I find that to be a pretty dang accurate statement. Both are capable.
CZ 455 is switch barrel/caliber capable, and has Match barrels available as well. If I had to start over again, I'd likely go with the 455 just because of the availability of Match barrels.