The two most accurate rifles I've owned in my life have been a .243 Tikka T3 and a Howa Mini in 6.5 Grendel. Both would print 1/2 MOA groups when the nut behind the trigger did his part. Day in and day out, I'd have to give the accuracy edge to the Grendel though. Boringly accurate.
But the real edge (and some of you are going to laugh, but go ahead...) is in felt recoil. No, the .243 isn't bad at all for a grown adult. BUT, the Grendel has to me, about 1/2 the felt recoil of the .243 while still cranking out impressive numbers downrange for all practical hunting purposes. We don't need 100 grain bullets that go 3000 fps. for 99% of the hunting we do. A 120,123 or 130-grain bullet going 2400-2500 out of the pipe is plenty, or should be with the right bullets. And if you can get "plenty" of oomph with recoil that anyone can cope with, that keeps you on target and keeps you from flinching, then why not take it?
I was pretty down on the Grendel after seeing questionable results on game a few years ago, but the buddy I sold mine to sold it back to me at a price I couldn't refuse, so I'm once again a Howa Mini Grendel owner, and I have a renewed interest in the round - particularly with finding the RIGHT hunting bullet for it. So I'll continue my search with the little gun, particularly because it is so obscenely accurate and easy to shoot. Doesn't hurt that the rifle weighs just 5 lbs. 9 oz. after I put it on a diet.