OK, I feel like stirring the pot a bit:
While there might be something "magic" about the 6.5x284 (which there isn't, aside from acceptable velocities and a high BC), the biggest factor in the "awesome" performance and acceptance is the fact that "shooters" are the ones who are using them. You know, they are actually being used by guys who will practice and make "perfect" rather than just hoping top hit a paper plate at 100 yards!
These guns get shot, tested, ballistics run on the computer, great scopes installed properly on them and a whole lotta "press" about them.
Me thinks that if you did all that to a rock, you'd have a damn fine rock!
Yes, the 6.5 is pretty fine but MOST hunters have ZERO idea or skill to PROPERLY take advantage of any ballistics gain over a "standard" cartridge.
But they are damn cool and certainly adequate, for most applications, and damn sure wonderful if a guy shoots one a bunch.
My 2 cents (and take it as a personal compliment if you ever plan on raving about a particular cartridge)
Zeke