I was never particularly impressed with Holiday. His body attack could give him a potential avenue to victory here, but overall I'd favor Diaz on the basis of his greater speed and pop in his punches.
I don't think there's too much of a gap between Holiday and Diaz, but yeah I do think Diaz was a bit better and should be favored here.
I love fights like this. Those hectic, ridiculous punch-'em-ups where both guys just don't stop. Sort of like Dorsey vs Kelley or Diaz vs Marquez. I tend to think Diaz was a little bit better than Holiday though, and would win a close decision in an excellent fight.