Good Engineering laptop which is also good for gaming at UMD

So I am still searching for a computer…I have decided on a Dell because the IT tech store says they work best with Dell and Apple warranties…but I am still deciding to from UMD http://premierconfigure.us.dell.com/dellstore/config.aspx?cs=RC1367124&oc=rcRC1367124-4092756…which has a 3 cell battery

or Costco’s http://www.costco.com/Dell-Inspiron-15-5000-Series-Laptop-%7c-Intel-Core-i7-%7c-4GB-Graphics-%7c-Backlit-Keyboard.product.100218051.html…which has a 4 cell

Of course they sell you on the idea that if your computer crashes they can give you one to borrow…But I know a lot of students say to have a long life battery…Its a couple hundred dollar difference because it shows a promotion of 200 gift card, sleeve and a 8GB flash drive (if that promo is still on, it was during orientation)…However UMD is i5 and Costco is i7

Can I get any suggestions and if you experienced trouble going to IT with a computer you bought from the outside…I don’t need a 2 in 1 but that seems to be the one UMD has and its a hybrid hard drive, 13.3 inc screen in comparison to Costcos SATA drive, 15 inch screen.

these are the 2 I decided on but can’t make the final decision. any more pro or con experience I should know before making this decision.

thanks for any feedback