Hmm... This is really hard. I'd say they're about equal.
They're completely different types of songs. The Edge Of Glory is a power ballad that's meant to sound epic, and We Found Love is a dance song which is simpler by nature. They're equally well done in my opinion, though.
But to be honest ( Navy don't shoot me ) I will go with Edge Of Glory, i love We Found Love to death its in my top 10 Rihanna tracks but Edge Of Glory is hands down the better record and one of Lady Gaga's best to date.