Came across this article comparing the baking performance of various high-end convection ovens:

https://blog.yaleappliance.com/best-convection-wall-ovens

To summarize, they tested Wolf M and E series, JennAir single fan and dual fan models, Thermador Masterpiece and Professional series, Miele, and Gaggenau. Of those, they liked Wolf, JennAir dual fan, and Thermador Masterpiece the best. The JennAir's dual fans arranged vertically seemed to make a significant difference in top-to-bottom evenness compared to the single fan model from the same brand.

I wish they could have been more consistent in their testing. They did at least seem to use the same pans in each oven, but they made different types/sizes/numbers of cookies. Additionally, some models only seemed to be tested with cookies or cakes and not both. It would have been nice to see side-to-side comparisons of exactly the same things baked in different ovens. I wonder if this explains why the Thermador Professional seemed to do worse than the Masterpiece even though in theory they should have the same convection system.

Still, it's refreshing to see someone do an actual test and publish the results, and an appliance store no less. I thought it would be helpful for folks shopping for ovens, especially since your ability to test these ovens in person might be limited due to the coronavirus.