Update: Miley Cyrus won this round! Click here to vote for her Smilers in the Semi-Finals!

Rihanna and Miley Cyrus have a lot in common: Incredible careers, envelope-pushing tastes and, of course, amazing fanbases! Given how loyal the Rihanna Navy and the Smilers are, it's tough to choose which fandom goes harder. But because this is March Madness, we've gotta vote: Who has the best fanbase?

There's no doubt that Rihanna's fans have her back 100 percent. (She was even voted PopCrush's Hottest Female Star of 2014!) The singer is always experimenting with new looks and different sounds, but her loyal Rihanna Navy always support her. As Rihanna gears up to release new music in 2015, we're confident that her devoted fans will be right by her side the whole time.

Speaking of diehard fans, Miley Cyrus' Smilers are a force with which to be reckoned. Even as Miley transitioned for Disney darling to one of the biggest pop stars in the world, her fans never wavered. If anything, they've grown even more loyal, racking up more than 700 million views on her "Wrecking Ball" video!

Which fanbase is the best? You can vote once an hour until the polls close at 3PM ET on March 17.

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