Ignition, that depends on what you mean by "casual plinker."
There is no question that the Finnish Mosins are finely crafted, highly accurate, and richly historic, but for a "casual plinker" who wants a fun and reliable milsurp rifle, I see no reason why a Soviet surplus model for under $100 wouldn't be perfect.
Barrel length is a matter of personal choice.
My M44s are of the short variety. M38s and the various cut-down Mosins also fit into this category. They're loud. They kick like mules. They are fun to shoot at night because they look like flamethrowers.
The 91/30's longer barrel has some tangible advantages. You end up with higher muzzle velocity, better accuracy, and for some reason (perhaps the higher mass of the rifle) less felt recoil.
Which one is better? For fun shooting, I love my M44s to death. I still want a 91/30, though. I hate to cop out and tell you to buy both, but that's what I'm going to do.