I have to agree with lawdog. "Best" is in the eye of the beholder. Huntsman points out that it refers to the 6.5 that will "take care of all your hunting needs." As I pointed out, in way, it makes a great difference as to whose hunting needs are being fulfilled. I know this seems like a lot of semantics, but I'm kinda tired of gun mag articles that propose to inform me of the "best" of anything. Since there is no way to quantify a single "best" for everyone's needs, I chose to use the word "favorite" which captures the subjective nature of the issue.
Since I live in the East, and will seldom encounter any hunting ground that requires the kinds of shots that require a hottie like the .264 maggie, I'm not particularly fond of belted cases and since I'm a bit of a traditionalist, my choice is the 6.5 Swede.
As for the .260 Remington, it is the ballistic twin to the Swede and is designed to work in a true short action. That was, and is, Remington's figuring with regard to the round. And, since they were particularly intending to chamber their cartridge in their model 7, they figured they were creating one heck of a package for many deer hunters, a fine balance between killing power, compactness and lightness of rifle and recoil light enough for even the very recoil sensitive hunter. I think they succeeded. And, since they were not going to be chambering the Swede in one of their rifles, they were offering Swede ballistics to Remington fans.
It also offered a very inexpensive source for brass, since the Norma stuff was, and is, very inexpensive. One could just get Remington brass or form his cases from a number of members of the .308 family of cases. The Swede's unusual head size prevents forming cases from any other parent cases.