I think it's gonna be different results for different applications.
We just got through dealing with this on my buddy's '68 Chevelle. He picked it up a couple of months ago. Even in June, with 85-90° outside temps, it would routinely run 220-230° water temp with an electric fan running. The trip home was filled with stop & go driving, as we drove up through Mt. Washington and basically hit every stop light that we could find...
After we did some inspection to make sure it wasn't something else mechanical, he took the electric fan off, put the factory shroud on, and installed a mechanical fan. Temps dropped 30°. Even now with the weather being a little hotter, the same stop & go driving will not find the water temp creeping up.
I'm not jumping on anyone's side here, I'm just saying that there's a lot more that goes into it than just slapping an electric fan on and expecting stellar results. I think a lot of us are speaking from experience, but you have to take into account where we each are in relation to each other in the US.