which is better approch? More Traditional MVC or Creating libraries for code.

[eluser]pankaj[/eluser]
I am using code igniter for last one year and I have started using MVC approach with codeigniter itself. in Codeigniter user guides model section they mentioned "Models are optionally available for those who want to use a more traditional MVC approach." they have mention MVC is more traditional approach. But now I am getting confuse, and have question, which approach is better, using Model or "creating libraries" which having mix code for database as well as functionality.