MacBook Pro 17" Model MD311LL/A

I have a chance to purchase this new from a friend. I'm not paying full price ($2400) because this was supposively released in 2011, and it is already outdated. For instance, it doesn't have the latest Retina Display. The fact that Apple doesn't make this as a 17" screen anymore is either a good thing or there's a reason why the discontinued the larger screen. Does anybody know why, and what am I really giving up by not going with the latest MacBook Pro models? I can get this for just under $2K unopened and new so it seems like a good buy.