MBA vs. Vaio Pro vs. S7

I am currently thinking about getting myself an ultrabook for university. I'm a sophomore International Studies/English major with a possible minor in Computer science. My current laptop, a 2011 Sager NP8150 which is a monster with 16gb ram ssd and a 6990M, is absolutely worthless when it comes to taking it to class due to its battery lasting for 40minutes max on powersaver mode.

I find that I don't really play games anymore and live inside my browser most of the time so I thought its time for an upgrade. The most important things to me in a laptop are battery life and display. Every device I own has a 1080p display so I would not like to go below that.

Current devices

Galaxy S4, Nook HD+, Sager Np8150, 39" Panasonic - all 1080p

With my reasonining out of the way here's my question: I want to buy a Windows 8 ultrabook like the Vaio Pro/Duo 13 or S7 but I can't seem to bring myself to accept the prices of such devices. I understand that they're made from high quality materials and they have amazing displays but I just can't bring myself to believe I should be paying that much for those types of devices. my preferred configuration would be 8gb of ram, an i5, and and I'm fine with 128gb

with this in mind why would I choose a windows Ultrabook that would cost at least $1500 for a configuration like this instead of a MBA 13 (~1300 at that configuration w/ apple care)?

I'm not trying to sound condescending about it but I want to get one of the vaios but increased cost of a touchscreen, which I like but most likely wont use unless its a surface type device, and resolution don't outweigh the lower price, better GPU, and battery life of a MBA.

What would you do? I appreciate any help