By its very nature, graphics performance benchmarking is controversial; especially when you are doing it across different hardware architectures and APIs. How couldn't there be controversy? You are taking different systems with different performance assets and trying to apply a single criteria to measure performance. And not just any kind of performance, but graphics performance, arguably one of the most difficult characteristics of a computer system to measure.
The situation becomes even more heated when you try to take a series of performance numbers and boil them down to a single number that is supposed to be the final word on performance measurement. In actuality, everyone knows what the composite number is -- it's the performance equivalent of a sound bite (I'll leave it to the reader to supply the bite/byte pun).
The reason more than a dozen prominent vendors and researchers on the GPC Group take on this seemingly thankless task is simple: standardized performance measurement is desperately needed in the industry, by both vendors and users. But, just because it's a good cause doesn't mean everyone is going to agree about how to go about it. Good intentions don't necessarily lead to equanimity when it gets down to the dirty details.
Certainly the GPC Group has had its share of controversy. Compromises are reached, but the controversy never really goes away; it's endemic to performance benchmarking. As evidenced by the performance benchmarking results found in this publication, plenty of progress has been made. And, no doubt there will be plenty of progress to report over the upcoming months. But, as always, it's likely to be ushered in by controversy.