Is this a good value PC tower?

[Hero in a half shell]

I finally have a good excuse to invest in a more powerful PC as my current laptop wont run AutoCAD, and I'm doing a course on it.

I had a hunt around amazon, and found this tower for sale (new of course):

Spoiler

http://www.amazon.co.uk/gp/product/B00C72IR5O/ref=olp_product_details?ie=UTF8&me=&seller=

549 British pounds sterling (for some reason the Escapist is registering my pound signs as japanese characters!)

Quad Core Intel 3.2GHZ
Nvidia GTX 650 1GB VGA Card
Windows 8 Installed
1TB Sata III HDD
8GB ddr3 RAM

-Just a tower, no keyboard/mouse/screen.

That's the cheapest version of it as far as I can tell, but is it good value, and since it's already built can I upgrade it with extra RAM/new graphics card/whatever the same as a self built PC?

EDIT:
As is always the case I just did another sweep of Amazon and found some possibly better deals.

There's this:
http://www.amazon.co.uk/4440-1000GB-RADEON-Gaming-Series/dp/B00I3IKH72/ref=sr_1_17?s=computers&ie=UTF8&qid=1394581564&sr=1-17#productDetails

433 pounds sterling

Intel Core i5 3.60 GHz X 4
8 GB DDR3 1333MHz RAM MEMORY
No Operating System Installed
1 TB Hard Drive Storage Space
AMD Radeon HD 7950 Gaming Graphics

Which would be excellent if I can find my Windows 7 disk to install it.

My main question is if I buy a pre-built PC do I still have the ease of upgrading as I would in one I built myself, or could it be locked off or blocked in a way?

 

[AWAR]

snip

Well, the second one is much better performance wise and much better value as well. Though it doesn't list the power supply brand which is a bit worrying, but it's in a normal mid tower case so you'll have no problem upgrading it and other parts as well.

 

[Hazy992]

snip

Well, the second one is much better performance wise and much better value as well. Though it doesn't list the power supply brand which is a bit worrying, but it's in a normal mid tower case so you'll have no problem upgrading it and other parts as well.

That was my first concern as well. However if the OP goes with something like this [http://www.amazon.co.uk/Cooler-Master-G-Series-G500W-Supply/dp/B00CVUW94W/ref=sr_1_5?ie=UTF8&qid=1394619718&sr=8-5&keywords=cooler+master+psu] he should be good to go.

Although I am a little confused as to why it says it only has 1GB of VRAM. The 7950 has 3GB.