Of the slow movements, I think the Haydn is possibl a richer piece of music, but harder to pull off well. And of the fast movements, the Beethoven is more exciting if you can play that one with appropriate gusto!
Keep in mind that juries at universities hear tons of pianists with fabulous techniques at auditions, so what probably will impress them more is if you can do something moving/exciting/interesting/of a high musical quality with whatever repertoire you select. So I would advice you to pick something that suits your temperament/musical strengths.