I was two 6.5 CMs, one with a Vortex Viper HS and the other a Vortex Viper HS-T. The scope quality is on par with the quality of the rifles they sit on, meaning they cost roughly the same. I have several Athlon Helos BTRs, and the same deal, they match what they go on. They're all fine so far, but I haven't done anything serious with them. All the Athlons have been "set and forget" and they've held zero. The Vortexes have done limited dialing, but they've returned to zero well and dialed accurately.
What kind of reticle do you want? I prefer a traditional SFP duplex for hunting, but the Athlons have the FFP MOA reticle and it hasn't bothered me.