In my personal opinion, not that anyone need agree with me...
Rihanna & Beyonce >> Lady Gaga >> Katy Perry
Her face is so generic in showbusiness, she is beautiful but she isn't as much of a stand out beauty as the others. Lady Gaga gets hated on but I personally think she is hotter than Perry, she is unique and I find that beautiful.
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Rihanna too. 
