I'm sure it will change, but as of now I believe Sinestro has displayed incredible control of the ring and Superman has done little to nothing impressive yet.
__________________
"And then there was nothing. A once broken something now void.
And on the first day, Doom spoke... 'Be.'
And then there was life."
Most likely that I haven't seen ALL Superman DCnU appearances but those I saw he went through everyone and everything like a knife through butter till now, except Darkseid.
__________________
Sig made by my mate, the one and only One_Angry_Scot
The manner in which the omega beams ripped into his body makes me see this as sinestro's fight. Superman's durability seems very suspect to say this least.