If I'm not mistaken, the 91/30 has a longer reach with its bayonet than the m44 and the kar98k, which gives it an advantage if you're good at gauging range and keeping yourself in the sweet spot where only you can strike. That's hard to do though when both you and your target are dancing around like a mix between jousters and sumo wrestlers.
Regarding the carbines, I use the m44 because of the bayonet and never touch the m38, but as far as shooting is concerned, all three rifles feel fine for me and the faster bolting and shouldering times don't impress me much. It depends on mood. If I want to feel fast and agile I use the m44, if I want to feel like I have a freakin' spear in my hands that spits lead, I use the full rifle.