Love songs in pop music make up a very crowded field. That makes it difficult for any individual song to stand out, but Katy Perry did it on "Teenage Dream." The quality of the song itself was demonstrated further when Glee's version became one of the biggest hits the show has had yet.
After landing in the top 5 as featured vocalist on debut singles from B.o.B. and Travie McCoy, Bruno Mars went straight to the top with his first solo hit. His "Just the Way You Are" is likely to supercede the Billy Joel classic of the same name in the minds of many pop fans.