It's basically a 257 Roberts in a smaller package. It's also designed for higher pressures.
The 257 Roberts, when loaded to similar pressures in modern rifles will beat the 25CM, but not by much or enough to make a difference for hunting Deer and Black Bear size game animals.
The 25 cal market is not huge, mostly due to a lack of interest.
Most folks I know are blinded by the velocities which can be achieved with lighter 75-100 grain bullets. However, when the 115-120 grain bullets are loaded, the 25s really shine.
If you thing the 6.5CM generates light recoil, the 25 will be even lighter, with similar accuracy and field capabilities, when good bullets are used.
My only concern would be for those who don't handload. Finding LGS or even Big Box stores which carry commercial loads could be difficult.
I have a friend who was talked into purchasing a rifle chambered for the 6mm ARC. Beautiful rifle, extremely accurate, "if he can find ammunition"
He's not the type to purchase more than one or two boxes, so it's a constant issue for him when he's looking for ammo.
These cartridges are floated regularly but often don't last long and become "hand loader only" safe queens.
Many of the rifles I've torn down to build custom rifles were chambered for "flash in the pan" cartridges and sold to folks who only shoot factory ammo.
This should be a consideration for anyone looking to get into this as a cartridge of choice.
That being said, try finding an LGS which stocks a good selection of 257 Roberts or 25-06, which will perform as well as the 257CM will with factory loads.
IMHO it should be a great little cartridge, with great potential, IF you handload.