Hi, might i ask why you dont belive you can build one, its much easier than anyone depicts, all you need is a common sense and proper guidance(thats where i come in).
Lets start with the advantages of building yourself, first of all there is the completion,once you get the build together and all working you will feel happy and super excited, almost like a kid who just completed an awesome lego building. Second there is the computer itself, the prebuilt systems are always so unballanced, if you look at the hp for instance, it has a 4790 as processor but 270 as gpu, 4790 is the of the line while the 270 is only a low-midrange enthusiast card. the motherboard is probably some nobrand, same goes for the powersupply,then you have three tb of harddrive but no ssd, in 2014 every computer above 600£ should have a ssd.
Well, what are the fears, often its breaking stuff, but i tell unless you are really.really careless its hard to damage the components. SO recommend you this, buy components and build yourself, its a great experience.
ok here we go:
http://uk.pcpartpicker.com/p/kWGwD3
with this you get a 240 gig sdd(super fast harddrive), a nice motherboard,a cpu cooler(which means lower noice and longer lifespan),and a beastly gpu. its 30 fps faster than the 270x and the hp was had a 270 which is slightly weaker than the 270x.
then you get a psu which almost got perfect score everywhere and has a ten year warrenty and lastly but not least you get a beatiful red case with a window to show of your pride. Alos thnx to the motherboard and psu its is prepared for a second gpu. you also get a 27 inch monitor with 5ms input instead of 7,
What do you lose then, well you dont get a i7 anymore but since almost no game utilizes more than 4 cores an i5 is plenty enough, you get 8gb of ram since you dont need more for gaming, you also downgrade from a 3tb to 2tb drive but i mean which gamer uses that much storagre
well thats it, tell me what you decide to do