So we don't have a way to objectively measure the quality of training of troops and compare it to others.

There were three levels of training among Finnish soldiers. From best to worst: Civil Guard members, normal reservists and war time conscripts.

There were tens of thousands of men who were members of the Civil Guards in the mobilized army in 1939. The Civil Guard was a voluntary defence organization providing military training for members. Its members had their own personal rifles, which they could take home and shoot and hunt freely with, thus making the mebers excellent marksmen. Famed sniper Simo Häyhä was one of those. Civil Guards provided mostly infantry training, but there were also a few artillery units. When the army was mobilized due to the threat of war, the Civil Guard members were incorporated to normal army units and did not serve as their own formations.

The largest group were the normal reservists with no voluntary training. They had a year of service as conscripts behind them and maybe some refresher exercises. They performed well in the battlefield, so it seems that their training was good, but it is impossible to measure such things afterwards.

Due to economic woes a part of the age cohorts had been left without training in the 1930s. Those were called to arms as well, but only when the war started. They received a quick training and had very little ammo or equipment for training. They were used as replacements for losses and in rear line duties to free trained men to front lines.

The Finnish Army had been mobilized in reaction to Soviet territorial demands in October. This gave the units time to train together before the war started, although most of the time was spent on building fortifications.

One additional advantage Finns had was that their training was entirely for the environment where the war was fought. Soviets were trained to fight on Fields of Europe and Steppes of Ukraine, not in Snowy forests of Finland. Pretty much all Finnish troops knew how to ski for example. Ability to ski was so important that foreign volunteers who were not from Nordic countries were not sent the front lines even in the desperate days of March due to their lack of skill in skiing.

Some older men and a lot of the officers were veterans. Finland had fought a civil war in 1918, so there were so e of the veterans of that war still in fit to fight. Higher officers were mostly veterans of the First World War where they had served in German army as the 27th Royal Prussian Jaeger Battalion. Almost all regimental commanders, all divisional commanders and many other officers came from that unit. Of the active Generals only CinC Mannerheim and inspector of artillery Nenonen were from imperial Russian army. There were no generals without combat experience, highest ranking man who had not served in a war was colonel Airo, a later Quarter Master General during the Continuation War.