Which laptop model to buy?



So I laid my eyes upon the new Asus Vivobook with touchscreen. There are two different versions I can choose between.
- €399 version with Intel Celeron 847, 2GB RAM and 320GB HDD
- €549 version with Intel Core i3 3217U, 4GB RAM and 500GB HDD
The other specifications are the same for both laptops.

I will use the laptop on the go, for instance when I'm travelling by train. I will mainly use it with simple programs like Office, Firefox and a PDF reader, but I am a multitasker: it should be able to run these programs together (with multiple open tabs and documents) without much trouble.

My old laptop's Windows 7 Experience Index CPU score was 4.5, which was more than fine for these kinds of tasks. The €399 version's Intel 847 should score a 3,9 on the Windows 7-experience scale, the €549 version scores about a 6.2.

Do you think the cheaper model is good enough for my demands, or is is better to buy the more expensive model? The main issue is the CPU; 2GB of RAM is enough in my experience and I don't care much about HDD space. Thanks in advance!