Speaking as someone who has personally experienced an Xbox 360 failure (mine is currently on its way to be repaired in Germany) it comes as little surprise that a recent survey suggests nearly half of all gamers questioned have suffered 360 hardware failure.
The survey, by Nofussreviews, polled 500,000 people and discovered that 42% of 360 owners have suffered hardware failure in some way. 55% of those people have needed more than one repair or replacement, with 39% needing either more than twice. The poll is slightly flawed in that it doesn’t account for the amount of time played or the area the console is played in, but these figures are still a lot higher than Microsoft suggests.
In comparison the PS3 had an 8% failure while the Wii was only at 1%.
Of course, these could be for consoles made before the new Jasper chipset (like mine) replaced the original chipset in 2008.
More about the survey can be found here.