Perhaps the title and focus of this article should not be specific for only Codeigniter, As any PHP framework has its own features and benefits against custom PHP development. But I love Codeigniter framework because of its very easy configuration and flexibility of going into very depth of development. I have been working in this framework since 2008, So I have pretty good reasons base on my experience with this framework that why using Codeigniter is a lot better than going to raw PHP or custom development.