there's no difference between wood and poly. Healthy bees have no problem at all coping normal winter temperatures. Maybe Canada, Northern Scandinavia including Northern Finland there's a small advantage, but probably not.
When I started with polyhives 1987, I compared 2 polyboxes for brood and 3cm thick pine boxes . The difference of build up was huge. Poly hives brought so much more honey, that I could pay two polyboxes in first year to each hive with that extra honey.
Finish beekeepers have allways used insulated hives.
Uninsulated hives use 50% more winter sugar.
In Michigan USA university recommends to use 50 kg sugar in winter and 3 langstroth boxes. In Finland we use on average 20 kg and prefer to use 1 langstroth box.
With electrict heating I found 20 years ago, that a big hive can produce 3 fold brood amount in May. The reason is mathematic formula of ball volume.
The more warmer the hive, the better the colony can keep the brood ball alive over freezing night in May.
It is easy to compare wooden hive and polyhive. But guys do not mind.
The thing is not to go alive over winter. Biggest advantage is spring buildup, and how fast the colony is able to forage real yield. Even if I tell this, guys say that it is nonsense.
When I was on Beemaster's forum, Californian beekeepers adviced Michigan beekeepers, that bees do not need insulations. California may have +25C in December and Michigan may have -25C. Those advisors were mote than frustrating.