I've only seen pieces. I was really enjoyed Kate Winslet's work after seeing her in Heavenly Creatures (really cool early Peter Jackson film), and I've always liked Cameron's movies, but the Titanic story itself wasn't a big draw for me. I'll see it one day.
It's interesting that the film draws different crowds. Obviously there's people interested in the wreck, but also those who want to see it for Leo and or the romantic plot.
I do think it's funny imagining some stuffy historian in the theater, keen to scrutinize the film's accuracy of the events, but first having to sit through over an hour of dancing, kissing, and "Draw me like your French girls."