I can't say I disagree...
VGC is a estimate site... so only the companies have the real and reliable numbers.
But one things that makes the VGC estimate close to real numbers are the frequents adjustments... so if you look at the BF weeks numbers I'm sure they will be wrong for at least some weeks but when the time got passed the numbers starts to be more accurate.
BF 2012 is more accurate today than BF 2013.
And for a estimate site the number are good for hardware but not so much for software.
The wrong are the people that thinks in VGC like a tracker site... it is not... it is a estimate site.