I confess, I've ignored the 6.5's all of my life. But with the interest in the 6.5 CM I bought a Ruger Predator in the caliber about a year ago just to try the round. All I can say is that the 6.5's live up to the hype. The 6.5X284 does the same thing about 100 fps faster.
I've not spent any real time hunting with the round but I've seen enough 1st hand reports to feel confident that it does everything a 270 does as a hunting cartridge at ranges inside 500 yards. And beats it beyond 500. As a target round it beats 270 and 308 handily. That is farther than I have the skills to shoot, but at "normal" hunting ranges I'd hunt any animal in the lower 48 with any of the 6.5's with good bullets.
My problem is that I have several nicer rifles than the Ruger in other cartridges that work just as well and I simply prefer to use those to hunt with. And at this stage of my life I'm not sure I want to invest the time, money and effort into putting together a "nicer" hunting rifle in another cartridge.
I could hunt with the Ruger, but at this point it is an inexpensive, yet very accurate range toy. But if I were younger, or advising a younger hunter, I'd look very hard at one of the 6.5's as my go-to all around North American cartridge. And I could change my mind about that. The older I get the less I like recoil. I sold a 300 WSM to fund the 6.5 CM purchase and consider the 6.5 an upgrade.
The 260, 6.5X284, 6.5X55, 6.5-06, 26 Nosler, 264 WM and 6.5CM all pretty much accomplish the same thing. Some shoot a little faster and flatter, but even the slowest of those rounds are capable farther than most shooters can shoot. The 6.5 CM is already out selling all others and is the easiest way to get into a 6.5.