Samsung series 5 urgent opinions required (I have 3 hours to decide)

I'm looking at getting a touch screen ultrabook - with a slim profile, and nice design, for a little as possible. I've spent too much on laptops, tablets and phones and now I'm happy with my Lumia 925, I need something functional and practical for work/studying.

The device to replace:

HP ENVY M6 with an AMD A-10 CPU, 2.3Ghz (4600), 6GB of ram and a 1TB harddrive, weighing around 2.5KG, 15.6" with dedicated and integrated graphics and beats audio. (Going to sell for around £290-350)

The option:

Sasmung Series 5, Ultra Touch with Intel Core i3 (3rd Gen) 3217U, 1.8 GHz, 6GB of ram, 500GB harddrive plus a 24GB express cache, 13.3", touch screen, weighing in at around 1.6KG. (Going to cost around £330-400)

The use:

-Travelling (Trains and coaches)

-University work, essays, typing notes

-Emails for work

-Facebook, Twitter, tumblr

-Other casual web browsing

-Watching on demand tv and films

Must have:

-Slim profile

-Lightweight

-Strong battery life (4-6 hours)

-Touchscreen

-13"-14"

-Sell for around £300-400 used/refurbished/new (As I'm sick of spending a fortune on things every few months)