My 2 cents is, just based on my amateur opinion and from what studies I have read and what I've gleaned from personal conversations, public discussions, and watching not just professionally produced porn but also a lot of homemade sex videos, in general men of African descent take the cake. And this is fairly uncontroversial to my mind, despite the sensitivity of the topic being so obvious.
I have read the push back rationalizations about the distorted impressions of professional porn, and I could grant a small degree of credence to this - however it fails to address or even acknowledge, let alone answer for, the disparity in available talent pool size.
Consider that almost all the professional porn we see is produced in America or Europe. Consider that white men outnumber black men in America/Europe by a ratio of at least 5:1, the fact that there is a preponderance of monstrously hung porn studs who are of African descent is nothing to sneeze at.
There are of course exceptions to every rule, and they number tremendously when regarding generalizations about populations of billions. There's over 1 billion Caucasians on Earth, and over a billion Africans. It's goin to be plenty exceptions out there people! And the exceptions could easily number in the millions, but still only represent just a tiny percentage of the overall.
Still, go back to my point about the disparate ratio in available talent pool for pro porn. White guys outnumber black at least 5:1 in regions that produce porn and employ legal citizens that must be tested for disease due to regulation. Yet despite this enormous advantage in talent pool size, the white guys fail to muster a cast of superhung porn stars comparable to what the much smaller talent pool of Africans can represent.
First, let's name some of the notable superhung white guys in professional porn during the past decade:
Chris Strokes
Johnny Sins
Danny D
Billy Glide
Erik Everhard
feel free to add on any notable names that come to mind, I know there are more out there
Now consider this list of notable superhung black guys in the same field of pro porn during the same period:
Lexington Steele
Jack Napier
Sean Michaels
Mandingo
Shane Diesel
Richard Mann
John E Depth
Boz
Ice Cold
Charlie Macc
Shorty Mac
Maxx Black
Rob Piper
Isaiah Thomas
Moe Johnson
Flash Brown
Rico Strong
Dredd
I think you get the idea. Just from what's available to see and judge for yourself, consider the 5:1 disparity in available talent which favors white guy representation, and yet when you pare it down to just the exceptionally large ones, it seems that the extra hung black guys out number the extra hung white guys by at least 3:1
Now just imagine if we could balance out the available talent pool so that it was 1:1 in terms of available white and black male talent.
So take that list of notable black male talent and multiply by 5. Then it goes from 3:1 to 15:1. Imagine there being 4 other Mandingos out there if you equalized the racial proportions in America. 4 more Shane Diesels. 4 more Lex Steeles. 4 more Jack Napiers, etc.