Might depend on the scope your using and if you can deal with the factory trigger well enough . My son in laws sport II with a burris 3-12x42mm scope that has fired 5 shot groups by him and myself that range any where from 1.5" to 2.5"moa with 89 and 69gr match grade ammo to mil spec 55gr . Thats good enough for what most folks need even with a dot optic on it . It can even be for some hunting with the right ammo out to 150 maybe 200 yards . Guess you need to decide what you may use for optic ? Lots to choice from .
We have never owned a brand name AR15 but have ar15 carbines . One for my wife and one for myself assembled at home from select parts and both are moa shooter or a bit less with scopes and other add on's for possible night time needs . Also one AR9 made from parts - fun gun .
I have three M&P Sport II's (my own and one for each of my sons). Mine shoots @ 1.5MOA with generic M193 (I usually use PMC XTAC) and my sons' rifles will do @ 2MOA.
The accuracy is largely dependent upon the shooter. If you have any intention of possibly using it for defensive purposes, don't alter/change the trigger......unless you do something like the ALG prepped parts.