No offense, but this is a stupid question. If you have both in your possession, you should know which you prefer. The 24-70 is sharper and heavier and some people prefer the weight, balance, reach, and IS of the 24-105.
People who care about image quality and bokeh will always lean to the 24-70, and those who enjoy the versitility of the 24-105 will lean that way.
If I have both in my hand, I would consider resale values... the 24-70 will not dip... but the 24-105 is flooded in the market right now and some prices go for as low as 650-700. So figure out your style of shooting and which is best in the long run in regards to residual value... which of course is the 24-70.