I shoot 308. Mmmmmaybe i would have chose 6.5 way back when. Probably not. I learned 308 with an fnc1, then m305, then 700police now savage 10tr. Lots of surplus rounds to cut teeth on. Still better variety available out there. I mostly kill pesky paper and match 308 is easy to find. Though it seems like a good one, 6.5 is a hunting round only, imo.
If you are capable, shoot what cartridge you believe in.
Full disclosure, i also shoot 9mm, not .40 and never ever a .45acp!