Katy. Because whatever she decides to do, she'll succeed.
If she decides to make more mature music, she'll be fine because she's already the queen of HAC radio (even Uncle almost went Top 5 there
)
If she wants to keep doing fun pop music, pop radio and pop media will be on her side.
If she stops doing well, she can reinvent herself easily. GaGa's image is very specific (while also all over the place, which is pretty hard to achieve). She's a stylized personna. Katy isn't. If something doesn't go well, she can do a 180 and fix it.
