I am just not sure what the advantage of the Creed moore is over the 260 Rem. As I understand it the bullet can be seated farther out of the case? But in order to do that the case was made just a very small bit shorter than the 260 Rem case? I got no problem with either round, I like 6.5's. But to sell this idea as I understand it you really need to have a good line of BS!
CM case is shorter, but has less taper and a steeper shoulder, improving capacity for the length. I have heard conflicting reports of the case capacity, some claim it is essentially the same as the .260, but others show it holds 1 less grain of H20. That is probably close enough not to matter.
The advantage as I understand it is when using longer/heavier bullets in the 260, you need to seat them farther into the case, eating up some powder space, particularly if you are loading to magazine length for a gas gun. If you are shooting a bolt gun, it doesn't matter as much.
6.5 it is kind of a sweet spot, the Swedes figured that out in 1894.
If someone wanted, or could only afford, one rifle to do everything, the .264 bores are a pretty good option. The Creedmore doesn't really give anything up over the 6.5 Swede or .260. but can shoot the long, heavy-for-caliber bullets in a short action, which the others cannot (at all for the Swede, or well for the .260, depending on the rifle). You can use it for hunting anything from ground squirrels to elk, and with the good match bullets available, you can use it for LR target shooting. A quick look at midway for Ammo shows 49 options for the CM, 20 options in .260, which is not that much better than the Swede at 17 options.
There are certainly others that can do the same thing, but generally with more recoil. Hell, I did with a .308 when I was young and broke.
For the record, I don't own a 6.5 CM, but am a fan of the 6.5 in the Swede, Arisaka, and in my LR rig, 6.5-06.