Retina Macbook Pro 15" (from Feb.2013)

Just looking for some advice on getting a new macbook, I'm either grabbing this 15" retina, here are the specs..

15.4-inch (diagonal) Retina display; 2880-by-1800 resolution at 220 pixels per inch

2.4Ghz quad core i7 with 6mb shared cache

8GB of 1600MHz DDR3L SDRAM
256GB Flash Storage
720p FaceTime HD Camera
NVIDIA GeForce GT 650M with 1GB of GDDR5 memory

Above costs $1699

*EDIT* Also noticed there's one with a 2.3Ghz released Oct. 2012 for $100 less. Whats the difference there??

Or I can go for a new 13" without retina, specced out to its fullest meaning a dual core i7 at 2.7Ghz, 8Gb of ram and a 1Tb HDD. Which is $1314 with an education discount.

Which is worth it?