They're two completely different watches, so it's hard to compare them. I had the money to get a Rolex, Cartier, or J12. I chose the J12 38mm in white with diamond markers. It just matched my personality more. It stands out sooo much and I get compliments on it almost daily.
Rolex watches are beautiful as well, and I do agree with what everyone else said that they are more timeless. I plan to wear my J12 to death for a very, very long time, but that's because I love how much it stands out.