The only thing the rMBP has going for it is a good display. Go do some research on Dell and HP's small business laptops. They blow the rMBP out of the water wrt to value. The Latitude 5 and 7 series by Dell in particular are fucking awesome.
You're comparing apples to oranges.
Best 15" model I could find was the latitude 15 5000. 47 WHr batter. 4.6 lbs. Almost twice as thick.