I know I'm probably in the minority on this one, but I'm actually gonna go with Superman on this one. Admittedly Sentry has an impressive power-set, but we've seen him go all out without Void-ing out before (WWH is the only time I am familiar with so that is the version I will use) and frankly I'm not that impressed. IIRC it was later revealed by Reed Richards that Hulk had reached "World Breaker" level while battling the Sentry. Taking that into consideration, if you want to use something like collateral resulting from an attack as your barometer for shear power, the amped Red She-Hulk in HOTM was much more impressive than the all out Sentry in WWH. Secondly, Superman is a much smarter fighter than Bob is. It wouldn't take much for Superman to throw him off his game. Lastly, as stated before Sentry was only able to stalemate Hulk. There isn't a doubt in my mind that the same version of Hulk would give "normal" Superman a run for his money. A Superman that isn't holding back however, is a much different animal. Not holding back, Superman would wipe his ass with the Hulk that stalemated Sentry.