Need advice on which gaming laptop to chooss?

I'm needing a powerful laptop for both study and gaming as I'm having to ditch my desktop for a few months. I'm a casual gamer so whilst wanting to play intensive games like Tera Online, or GTA, I won't be playing in the laptop for hours on during the day but yes, games like Tera or GTA are what I mostly play. (Tera being very CPU dependent).

So, I've been researching some gaming laptops needing advice on what to choose. I'm on a budget of £700-£900 so the laptops I have come across are somewhat cheap but reliable-looking (or good enough to look like a gaming laptop to me.

Lenovo Y50 - Intel i7, GT860m
Asus G551JM - Intel i7, GT860m
MSI GE60 - Intel i5, GT850m
(All found at Curry's/PC World)

There the only 3 I have found and need help on choosing. They all look aesthetically pleasing and looking at the specs they all seem very similar so I don't exactly know what to choose.
However please do recommend other gaming laptops out there and in case here are my laptop preferences:
-Screen Size: Preferably 15.6" (Want to bring it school etc…)
-Processor: Preferably Intel i7 or similar?
-Graphics card: Preferably NVidia or similar? (Want to play modern games at a decent frame rate e.g even 40fps would be fine for me on games like BF4 but obviously higher would be cool)
-Design: Really like the design of the lenovo y50 but design doesn't matter to me
RAM: 8GB+ (is 8gb enough?)
Last but not least, I'm looking for a laptop that can last me a couple of years.

EDIT: MSI GS60 not GE60