PS4 has a more powerful GPU than a 7850, the CPU and GPU are also on the same die, making the technology more efficient and latency between those parts much better.
You can pick up a PS4 for £299, with a game right now, PS Plus also gives you hundreds of pounds worth of games and just started giving out AAA retail quality games, there's no comparison for the value and price to performance ratio a console offers.
Of course you can spend more money and get a vastly superior spec than PS4, but when it comes to value the platform and a PSPlus membership far outstrips the value of a PC and the cost of trying to buy the same amount of games through say a service like steam.
Even if you could buy each of the games on PSPlus for say £3 each, 3 games, a month is £9X12=£108 and you're never going to be able to buy those same 36 games all for £1 each on PC, not even in a few years after they came out.
Injustice is £7.49 right now and Secret Ponchos is £10.99 on Steam, Infamous First Light is cheapest on PS Store at £10.99.
With a couple of months worth of content it equals the cost of a year's PS+.
Basically the games included in the instant game collection end up paying for a full year's membership when you take into consideration the price those games would cost you to buy on their own.
Consoles continue to have the value proposition locked up, facts don't agree with anything else!
