680 to 780 performance increase costs about ~£40 for every ~10% extra, is this going to happen every new series now considering the 780 is the second fastest card in the Nvidia lineup?
Looking around the net, loads of very, very unhappy Titan owners out there too, not every owner I may add, but more unhappy by far.
Its actually quite true, AMD have (Historically) had more issues with drivers/etc than Nvidia and thus have acquired a rep for it
despite things being much better these days (much better not equalling perfect of course,
recently an issue with the HD7900 drivers that went unfixed for a year saw a lot of us forced to move to GTX600 
)
Some Nvidia users are still suffering from bugs that haven't been eradicated from launch with the 6 series that keep coming back to haunt them.
TDR issues are harder to eradicate with the 6 series as there is next to no way of applying extra voltage for an easy fix, leaving down time for RMA's.
AMD have their problems too, it's not a one way street, but IMO, AMD's appear to be getting 'better', while Nvidia's having more problems than usual.
The recent AMD CrossFire frame time issue is a prime example of net marketing, it's not as 'good' as SLi, but there is no fanfare with the 7 series having superior frame times in single card mode-where most are being used.
Users have been forced to go both ways, it's not a one way street by far, take a trip to respective official forums and you'll see countless unhappy users from both camps, saying they are off to the other team.
Historically, Nvidia have had hardware failures on simply a massive scale in comparison too, with faulty drivers burning out gpu's and faulty assembled/designed discrete gpus on laptops-put a search into big G for laptop gpu reflow, then come back and tell me AMD have had more issues with their gpu's, remembering we are talking AMD, not ATI.