Go to a race track and look under all the cars. Ford 9" is the majority choice and there is a reason for it. They are hella stronger & cheaper to build with better gear selection than an 8 3/4 ever had to offer and easier gear swaps than a Dana 60.
I think you need to re-read my original statement/post. I said the 9" is cheaper to build and has a much much bigger aftermarket following. Now an 8.75 and 9" are about the same strengh out from the factory period. A Dana 60 is much stronger than both from the factory period. Now if you want to build a rear the 9" and will be cheaper hands down. Again all of this is stated in my original post (though I should have been more clear about my statement being from the factory). I've seen 8.75/9/D60 in all kinds of race and street cars, I've also seen everyone of them blow up. Like anything else, it depends on how you treat it.