Why Finland

I prefer Finnish Mosins over Soviet.

I think it has a lot to do with never having a Finnish soldier aim his rifle at me.  I can't say that about Soviets or Czechoslovakians.

Then there's the sympathy towards a nation that seceded from totalitarianism.

Finn Mosins tend to come from two main sources for the receivers.  Guns they had when they said no to the revolution and guns they captured from those who said yes to the revolution.... ;)

They're also responsible for about half the Mosin variants!  Kiv/24, Kiv/27, Kiv/28, Kiv/28-30 and Kiv/39 are uniquely Finn.  Mauserized Mosin is how I've heard it coined.  Plus those new made guns on existing receivers are in addition to the original Model 1891 (Kiv/91) that they continued to make (remake) up to the end of World War Two.

Then there's the split between the Army and Civil Guard.  It makes me pine for an American version.  Even with the association the Civil Guard was given to the National Socialists after the war by the victorious Communists.

A Finn marked gun is probably a been there done that gun.  I like the chance that history clings to them.

This is yet another facet of guns that was influenced by gaming and sims.  GURPS: WW2's supplement for the Winter and Continuation Wars, "Frozen Hell" and the Finnish campaigns for IL2 Sturmovik made me aware of this theatre.