tl;dr - The Grenadier Gauntlet is chef’s kiss but the rest of the selections range from fairly bad to merely okay.
I’ll try to keep this brief:
The Kickback - It’s the starting weapon, I get it, but that doesn’t mean it should inherently be terrible especially since you (in theory) replace it within an hour or so of playing, never to be used again. Focusing on knockdown (stopping power) over AP and Punchthrough is a big mistake. To differentiate this weapon from the Ripper Gun, the Kickback ought to have enough punch through to penetrate a horde of Poxwalkers at least two deep. It should also come with decent AP so that the Ogryn player at least has the option to select for a range weapon that can provide for AP. The harsh reload speed and overlap with later options really necessitates this, I feel.
Ripper Gun - I have played with all three options. They’re basically the same. Non-AP, non-Punchthrough, slightly different range, spread, and one only has burst fire. There isn’t really anything here to make the individual variants stand apart from one another. I don’t fundamentally have an issue with the Ripper Gun’s design parameters as I do that none of them genuinely stand apart like the various Lasrifles.
The Rumbler - Putting it bluntly, I can’t see a reason for this weapon to exist in its current state. It’s the Knockback but it fires a grenade on a timer. It’s a good grenade, don’t get me wrong, but this game’s philosophy is built around closing, even at range. I have tried it, you don’t get more than one or two shots off before enemies are scattered enough or in your face. I’d reconsider this entire weapon from the top to the bottom. Other players carry grenades, better grenades even, or at least can easily refund their grenades at no cost (Veteran) without using up ammo drops. That said, I do think there is a place for a weapon like this, it just needs to be reevaluated.
Grenadier Gauntlet - Honestly? Well done. I had extremely high doubts that this would end up being a good weapon, but I would genuinely say it is the ONLY good ranged option that the Ogryn can take to address just about every role/enemy/mission type. That isn’t to say it is overpowered, it isn’t, it’s just that it is well suited to a game like Darktide and suited to the playstyle of the Ogryn Skullbreaker.
Twin-Linked Heavy Stubber - I had high, high hopes for this weapon as a sort of mass suppression gun that would send those nasty patrols of autorifle/lasrifle wielding infantry scattering for cover, but I can say after a few hours of trying it out, the thing doesn’t seem to suppress anything as you’d think it would. Further, the range is not bad but the accuracy is miserable. When I shoot a Ripper Gun at its appropriate range, I know that some of the pellets are going to miss, they just will, but there is always a fat nougat of pellets in the center that will hit whatever I aimed at. And this is usually enough to kill that enemy (barring armored specials/elites). The problem here is that the Heavy Stubber is firing out random shots as individual entities with their own pre-determined impact location. Which means in order for me to confirm I’ve killed anything at the this gun’s intended range, I need to hold the trigger down on the same location and keep firing until I have visual confirmation that it is dead, rather than prefire like I can with the Ripper Gun and keep just dragging the cursor around from enemy to enemy without stopping. This results in fewer kills, fewer hits, and overall a worse weapon. I saw it can actually do damage a bit of damage to Crushers/Maulers/Ragers but the range you want to keep yourself at from these enemy types while lugging a weapon of this size around does not align with the intended use.