So, given everything and taking some time to think, here's what I see:
With Speed Unequalized, Superman blitzes, as pointed about by Schnee One. Superman can literally pummel the Mad Titan to death before he does anything. With the match like that, this can't be added because it's a stomp, sadly.
With Speed Equalized, things get are far more interesting. We can easily say that these two are in the same ballpark for AP/Dura, which means that they have a true slugging match going on here. Both can fly. Superman resists the majority of Thanos' hax but in return I believe that Thanos has the better options for offense and defense.
His energy manipulation lets him counter Superman's heat vision and freeze breath. At the same time, Thanos can also release his energy blasts from his eyes, his hands, his eyes and hands at the same time or in omnidirectional waves of power, which gives him more attack vectors to work with. He also used his energy to just deflect/smack aside other energy attacks. Thanos can also generate forcefields to block energy and physical attacks. Should Thanos pull out the Life Manipulation, he'll drop Superman right then and there. However, that isn't Thanos' go-to response but it does give him a way to just say 'I win', so we count that more like icing on the cake.
However, Superman's level of experience does let him compensate for this to an extent, as he's fought these kinds of opponents before. Hence, Thanos will have to really work at this, but ultimately, he'd bring Superman down after they've wrecked a nice portion of the planet first.
