This is a bit of a tricky question because the answer will depend upon the personal stances of who does the answering.
However, the current consensus in the Finnish academic community is that Finland was first a victim of brutal aggression during the Winter War, and then from 1941 to 1944 a de facto Nazi ally, though with extenuating circumstances.
In the past, a major bone of contention was whether and to what extent the 1950s era "driftwood theory" was correct. This theory suggested that as a small, war-ravaged country, Finland basically drifted into a relationship with Nazi Germany through no fault of her own. Later research has challenged this theory, showing with archival and other sources how Finnish politicians and soldiers were far more active participants in building the relationship than the driftwood theory allowed for.
Right now, there doesn't seem to be much active debate about the decision-making by Finnish political leadership in 1940 and 1941; that is, the question of whether Finland could or should have avoided becoming allied with Germany, and why the decision was made, is not currently raising any strong emotions. (My personal reading is that there may have been better policy options and some individual politicians and soldiers were far too eager to join forces with Germany, but I really cannot justify assigning too much blame to politicians for the outcome.) However, recent research e.g. by Silvennoinen has revealed some quite uncomfortable details about the extent of Finnish military and security services' complicity in the murder of Soviet POWs by the Germans in Lapland and Norway during the 1941-44 Continuation War. Another somewhat active research stream is the extent of "Greater Finland" thinking among the decision-makers and the broader populace, and how e.g. the state church promoted such thinking - up to and including de facto compelled conversion of Karelian Orthodox residents to Lutheranism.
So, in summary, right now Finnish historians tend to characterize Finland in the Second World War as an unwilling participant who would've wanted to stay out of the war, but got drawn into it and then a) harbored revenge and b) got involved in some delusions of grandeur when it seemed that the German victory was imminent.
Unfortunately, English language sources are quite rare. The book I'd still recommend is Vehviläinen's Finland in the Second World War: Between Germany and Russia (namely, the 2002 edition). It doesn't include the recent research by Silvennoinen et al though.