Any die that ends up making the case neck straight with the body is good. Once the neck's straight and the mouth's not more than about .001-inch smaller in diameter than the bullet, most any seating die will put bullets in so they're very straight.
My own investigations show that bullets align themselves with the case neck when seated. Doesn't matter what type seating die's used; if the neck's crooked before seating, it's gonna be crooked after seating. I've used chamber type seating dies from Wilson, Bonanza, Vickerman, RCBS, and a few others whose name now escapes me. They all will help a bullet seated in a crooked neck be a little bit straighter. But when the neck's straight to begin with, standard seating dies will produce ammo with bullets as straight as all those chamber type seating dies do.
My bottom line: if loaded ammo's got crooked bullets, get a better sizing die.