http://en.wikipedia.org/wiki/Sapphire_Technology
Only had one Sapphire card, Sapphire Vapor-X 4890 2GB, was a great value card, only 2 year warranty, but I don't think many people keep a card 2 years these days before selling it on.
Graphics cards owned since 1998 = 13 / 1 = Faulty RMA from purchase, 6 year ago.
Motherboards owned since 1998 = 15 / 3 = Faulty RMA from purchase, last RMA 5 year ago.
All replaced within a week by OcUK, quite good really.
I don't think most people worry about RMA, unless it actually happens. The more wealthy customers won't care if something takes 28 days for RMA, I've seen people just buy new hardware and sell on the RMA replacements.
I look at it another way, if a company like KFA2, Gigabyte are willing to put money into providing customer service in the UK, then why can't other companies?
I mainly buy Gigabyte just out of principle, like I used to Abit, because they had a UK customer centre, other companies would soon change their tune if the sales dropped because they don't give a crap about UK customers.
Asus are just greedy (£) 142 million profit upto Quarter 3, 2012, they are massive and they could easily afford to provide a more efficient, quality service, but ASUS just don't care, because people will buy their products regardless.