I would say Gaga, but is a risk a risk if people expect you to take risks? idk. I would call them both sonically diverse, I'm not a massive fan of either one but their songs don't all blend together like certain other pop stars
Associating herself with Gaga was another big risk
No, sweetheart. Beyoncé added, like, 20 seconds to Lady Gaga's most generic single to date and enjoyed massive publicity as a result. That's not a 'risk'.
OT: Lady Gaga, by a large margin!
Beyoncé is one of the safest pop stars we have as far as music goes.