I'd favor Benitez clearly. Brown is the perfect type of fighter for him. Big banger, but able to be outboxed, countered, out-slicked, out-maneuvered, etc. Benitez by wide UD.
Benitez would win an easy UD over Brown, but if he got too smug, Simon would put his ass on the canvas a couple of times.
Brown's only chance is against the version that fought Bruce Curry. Otherwise, Mantequilla gets out-boxed into oblivion.
Benitez would win fairly clearly at his best, but if he plays arrogant and tries to stand his ground, Brown will be very competitive with his body punching ability.
Simon Brown is a bit underated, he could box and punch. He had bump in career when he dumped his trainer that got him to title and had Teddy Atlas for 2 fights before firing Atlas. His two fights with Tyrone Trice were classic, showed how good he could be, and his ability to fight tough and long. I would bet on Brown if he was slight underdog or if odds were even against Benitez. Problem with Benitez was he cut own career short with excessive cocaine use and drinking.
All Benitez needs to do is fight seriously. If he keeps his head clear and executes, he's simply too good. They are on different levels. If he doesn't go to the gym and stands still, however, he might get sparked. Brown hit VERY hard, and always brought it. He's more than a puncher; He had the ability to land. Benitez is the clear favorite, but he had lapses in professional attitude that make it an interesting match.
