The barrel is a 10 twist if I'm not mistaken
I do reload, and could reload for either. I'm really leaning toward the 222 simply due to the accuracy reputation sako has with that caliber.243w is nice and if you shoot factory ammo this would be the better choice.
If you handload, the 222 is the better cartridge. Easier to execute and follow through quality shots, spot your own hits (or misses), easy to find superb accuracy and much longer barrel life to boot.