Um, pdf27 - I’m not sure exactly what you’re referring to when you suggest the Finns didn’t do very well against the Soviets a few years later.
First, in the Winter War - another factor not mentioned was the brutalness of the winter, even by Soviet-Finnish standards. Many, many Soviets froze to death. Others became easy targets as they were framed by the light while trying to huddle around around bonfires during the long, long winter nights of that region. Soviet armor was nearly useless, and their oil froze, much as the German panzers’ would two years later. Further more, Soviet Propaganda had the invading soldiers thinking the Finns were ready to welcome them with open arms as liberators, and the reality was just a tad different…
The Finns did finally come to terms when the Soviets breached the Mannerheim Line. Numbers of estimated Soviet casualties are all over the map - I’ve seen at least one figure in excess of a million. The Continuation War was the next conflict, in which, as Germany’s co-Belligerent, Finland attacked to reclaim territory lost under the terms of the agreements at the end of the Winter War. The general consensus is they kicked ***, and actually, for reasons of grabbing defensible terrain, went a little beyond their old borders. However, they did not, for instance, help the Germans in their siege of Lenningrad, much to the German’s disappointment Things were pretty static until the Soviets finally counterattacked in ‘44. Badly outnumbered (as always), the Finns lost ground at first. What happened next becomes a bit murky. As I understand it, the Soviets’ position is that the Finns sued for peace while they were running home with their tales between their legs, and that ol’ Uncle Joe was kind enough to agree. The Finns’ position is more along the line of having recovered their balance and actually having stopped in its tracks (and some say started to push back) the Soviet juggernaut when Stalin agreed to peace in exchange for the Finns expelling Germans from Finland. Given Soviet attitudes and behavior elsewhere, which version seems more likely? Do you really think the Soviets would have ceased their invasion if they were about to roll the Finns up?
Stalin himself acknowledged the military prowess of Finland in a post-war toast: you can probably find the exact details with an Internet search. I recall reading German views of the Finns also as being highly favorable. An example: a captain in a German Mountain Division assessed in an official report (!) that any Finn was worth any two of his own men. As I think I said elsewhere, the Gebirgsjager were not exactly a bunch of sissies themselves. And the Finns did kick the Germans out of Finland (Lapland War), in a conflict some describe as bloodless, while others say it was quite bloody. Again, the Germans left – compare that to, say, their behavior in Hungary or Italy when their presence was no longer desired, and draw your own conclusions about how easily they left.
I would very definitely hesitate to characterize Finland’s army during WWII as performing “poorly” under any circumstances - excepting only the financial sense of the word. While I wouldn’t agree with Stalin on much, I would certainly raise a glass to toast Finland’s army.