Considering that, in the most current databook, Asuma is higher/equal in all stats compared to Neji, I see it being an interesting matchup. Neji's main style of fighting would actually prove to be inconvenient considering the Chakra-Infused Taijutsu Asuma uses proves lethal to near anybody. Asuma's intelligence as well as his strength advantage are his most valuable assets, besides of course his experience.
I see Asuma taking this high-difficulty simply due to his experience and his more broad skillset.