MSI had a lot of VRM issues on some of their boards.
http://www.pugetsystems.com/labs/articles/Most-Reliable-Hardware-of-2012-177/
Gigabyte was best, followed by Asus, ASRock, and MSI.
I'm sure I remember a number in the 2% range for ASUS. Might have been elsewhere.
With those small percentages, you need a huge amount of data to get meaningful results. Even mild bias can have a big impact.