At first glance the only "big" difference is that the HP does not have a media card reader or web cam, but has a better battery than the Dell. But also think about the company that you are buying from. As in if there is an issue with the product, how good of a service will you get? The following link will show you a survey that was done on computer companies.
So in the end I would recommend the Dell laptop, as the battery won't last longer but it offers more options and they have better customer service.