When someone sees the two cartridges side by side, especially a new or uninformed hunter, they will almost invariably choose the 30-06 for deer hunting because of its size in comparison with the .308. While I know for a fact that either will do the job, most people will choose to go the "bigger is better" route. Either cartridge will be as accurate as one can make it, but the .308 is easier to make accurate, in my opinion.