Specific advantage? Probably not?
Depends what you're up to, and what twist barrel works better for what you do I guess? Lots of fine shooting Armalite barrels out there, I'm sure lot's of fine shooting CMMG barrels too.
If you shoot 77gn ammo, you'd want the 1/7, 45gn-69gn for sure will work great with a 1/9.
Nothing wrong with either company I would think.