Which model Macbook Pro Retina 15 inch should I buy?

I am looking for a macbook pro retina 15 inch. I want a macbook pro with a dedicated graphics card, I was considering the new 2014 baseline model macbook pro retina but it does not have the dedicated graphics. I am now considering the old 2012 macbook pro retina with the Nvidia GeForce 650m graphics (baseline). I am wondering if this might be a good choice for me because I don't want to spend too much money on the purchase and if there is a big difference between those two models.