Every electronic component can fail, msi/asus have better build quality in general but sapphire is good too, nothing comes close to the cr@p xfx makes.
I will have to agree with you about XFX - really poor quality stuff given the price their cards retail at! Later revisions (newer stock) of most of their cards have a cheaper PCB with less voltage control over memory and core as well as cheaper, lower latency memory chips.
I've also heard stories about really poor capacitors used in XFX boards.
In my experience, some brands are definitely better than others. I had an Asus GeForce4 MX card which had just a little aluminium block as a cooler - the card still works on an old PC used for office work by my cousin (bought December 2002 - that's 8 years and counting!)
I had an Asus V9950 GeForce FX 5900 card - it tooks some serious stress from OCing, heck, load temps used to go as high as 90 degrees on that thing! It lasted till earlier this year, a very long time given the history of heat issues of the GeForce FX and the conditions it ran under (plus, it was bought in January 2004......). Even so, the card itself still works, it's just the thermal paste from the heatsink which was no longer able to hold the heatsink/fan combo.
My GeCube Radeon HD 3870 still works - all I need to do is plug it in and it boots right up. For a 3-year old card, I have no complaints either.
I also had an XFX GeForce 6800 GT card. Failed within 1.5 years. Any amount of dust accumulating in the closed metal HSF would cause it to overheat, so I had to specifically clean it's HSF by disassembling it every 1 or 2 months. I've never seen worse.
And now, this Sapphire.....I always thought Sapphire meant quality. But this too failed in 1.5 years. I can give it for RMA since it's still in warranty, but nevertheless, it is disappointing for me to accept the bitter pill that a relatively unknown brand like GeCube did better than the famous Sapphire......
Heck, the GeCube, the Asus - looking at them, you can tell they were built to last. Well-designed HSF, extremely solid PCB, no skimping on DVI slots either. Can't say the same about my Sapphire HD 5770 or any XFX card till date.
IMO, a better brand is always worth the extra money. If you cannot get a better brand due to budget problems or any other reason, it's better to go for a card based on the reference design PCB since those cards would likely be made by a contractor to NVIDIA/AMD's quality standards rather than the individual vendors (cooling systems, however, can still vary).
EDIT: For what it's worth, my GeCube HD 3870 was based on the AMD reference design PCB, and thus was probably made to AMD's quality control. The drivers even say "built by ATI". That's probably why it's still running great.....
