Generic? In a sense... But it's insanely catchy and her voice has never sounded more ethereal. Also, unlike most dance/house songs this actually has an instantly accessible and infectious melody that doesn't get dominated by the beat. This will definitely smash, and deservedly so.
I can see why people think that WFL and OG sound the same, but WFL is more contained, sweet, and tame. In a good way.
Overall, as one of my all-time favorite Rihanna songs, I think I PROBABLY like Only Girl more, but I'm gonna have to listen more. I love this song to death already, though. It's catchy and I like her vocals in it.