Although different states of mind iduring expression may effect your choice here

Question:Which do you think is more powerful? Nessun Dorma or E lucevan la stelle? Or you may choose your own after one of mine? Don't pick either of mine if you do not know both please?

I think E Lucevan La Stelle, extremely powerful.

Best Answer - Chosen by Asker: Which do you think is more powerful? Nessun Dorma or E lucevan la stelle? Or you may choose your own after one of mine? Don't pick either of mine if you do not know both please?

I think E Lucevan La Stelle, extremely powerful.

it's a difficult choice. Both arias were written by the same composer, Giacomo Puccini, who certainly knew how to elicit powerful emotions.
I think I will agree with you on E lucevan le Stelle because of the dramatic content: Mario knows that he has very little time left, and is remembering his life and love for Tosca.
in Nessun Dorma, Calaf is not quite at the same crossroad: he knows the next few hours will either make him or break him, but he's still confident of success.
Now, are you going to compare the ladies of these two operas as well??