Not all of these apply to everyone. Especially people who reload, and especially people who reload and get custom reamers made for match-grade barrels.
Vs. the Norma:
Pros:
More efficient powder burn
Fits in a standard magnum action (not Lapua bolt face)
May have an easier time keeping ES/SD down
Cons:
Less velocity, maybe 100-150fps
Vs. 300 win mag
Pros:
More velocity
Same story with ES/SD. It was designed around existing propellants to have an efficient, consistent burn
No belt
Probably better accuracy potential out of a factory rifle
Cons:
None from a performance standpoint. You probably won't find near as much factory ammo available for a while; until/unless it catches on.
Vs. the Nosler
Pros:
Factory match ammo, SAAMI chamber set up for long heavy LR bullets and accuracy
Non-rebated rim, better feeding
Probably better accuracy potential out of a factory rifle
Cons:
Less velocity
It falls somewhere between the 300 win mag and 300 Norma for velocity, it's set up specifically for long range/accuracy, and is an efficient case designed around existing propellants. The only overall downer I've seen is that so far, it only fits in CIP length magazines, otherwise it would be a simple re-barrel swap from 300 win mag in most factory rifles. If you hate on Hornady brass, I believe others are already gearing up to produce it.
I like to think of it as 6.5 Creedmoor's big brother. Very similar approach/concept in its development.