Google the difference between decent gaming PC capabilities and any next gen console......he's incorrect.
EDIT.....just re-read that to myself and I'm wrong, kind of....
For the price of a next gen console, you can only just match the performance....that's mainly because consoles are steeply discounted and they make their money back from game licensing....a decent PC will be WAY better in performance though.
Have a look at
Tomshardware.com for comparisons of GPUs (Graphics cards) and CPUs (the core processor that the PC is actually built around.
The £700 that this spec you've been quoted for is really quite high, but if the local contact and backup is worth the 200 or so quid that it's costing you, it may be worth it to you for peace of mind
I used to build PCs and concentrated in gaming stuff.....there used to be a white box kit supplier in Romford that I used a lot (branded parts but sold in bulk in plain white boxes, about 40% cheaper than retail boxed items) but in the mid-late 90's it became impossible to beat the big suppliers....I could walk into a Tesco or Aldi and buy a Medion PC (a good brand but budget image) and buy an off the shelf unit for a hundred quid less than I could actually build it for
Good luck to the small indies still trying to build PCs, but even though I've built dozens and know where to get bits from, if/when I buy my next one, it will be from one of the mass suppliers