The 30-06 is probally one of the best versatile cartridges ever made. And next to the 30-30 has taken as much game as any other caliber. Its a really good caliber. But it all boils down to what you plan to do with the rifle and spending the time tuning the accuracy of loads and yourself. The 243 is smaller and has less energy but it's all about shot placement. You can't go wrong buying the 30-06. Make sure you pick the right set up for your intended usage of the rifle.