nV News talks about this issue in a news post called Tail Wags the Dog
"However, over the last few months many professional sites who take much effort in producing many wonderful reviews now seem to be coming under attack from the Hardware manufacturers, or in some cases ‘Ah you won’t get our hardware to review if you do not do it exactly this way’. Why you ask, well more often than not the results do not meet the expectations of the hardware manufacturers and that is fact!
I personally know of three other web sites that have been hit with the same response. One in particular stood up and told a very famous graphic's company "to take a long walk off of a short plank" and trust me this is the polite version. All of us who take time and effort to produce reviews sit down carefully to accurately report back what we see using the items in question."