If you do not reload you will not get the best out of either cartridge and the choice is a real toss-up. You also need the proper twist (1-8) for the 260 to perform to its full potential.
I have owned both. I no longer own a 7-08, as I made that decision based on my 260s, all of them, being a bit more accurate plus the 260 will do everything a 7-08 will do and a bit more. You can easily use the 260 as a varmint gun by loading the 85 Sierra to just over 3500 fps. The little 85s will shoot sub .20 inch groups.
I guess the real deciding factor for the 260 VS other cartridges for me were the stats on the 6.5x06 and the 6.5x284. The 260 comes close to both of those rounds in performance while using about 1/3 less powder. I have a couple of 6.5x06s and decided not to build a 6.5x284 due to the performance of the 260.
One of my favorite 260 loads is the 120 Sierra MK over H414, running just over 3200 fps with .142 groups out of my custom SA Rem 700. The same load shoots .130 in the 260 Medesha upper for my AR-10. The AR-10 in 260 is a bad Hombre....
Ed