Impossible to answer those questions!
No doubt, the bolt guns are more accurate than other type actions! Sincethere are no moving action parts in a singleshot, they can be great too!
For brands of guns, that can be mostly a personal preference.
And here's where it really gets sticky; different guns, like different ammo! What shoots good in one, may not be worth a shet in others!
My M-70 .308 shoots the good old Core-Loct's better than all the other brands costing twice as much!