I think there are pro's and con's to both scientific and editorial reviews.
Scientific tire tests are made in a laboratory setting, with certain fixed environment variables (controls), so that all of the compared tires are compared in the identical conditions. These controls give a honest comparison between the tires, BUT are only really valid when the environment exactly matches the controlled environment that the tests took place in. I don't know what surface they use for testing, but I would guess it is a smooth hard surface. I ride big knobby sticky Kenda Kenetics 2.35's, on the road it feels like I'm dragging a body behind me, but on dirt, they roll much faster. I don't think a 3% rolling resistance difference in scientific conditions (assuming they are testing on a hard smooth surface) will be exactly the same in all trail conditions.
Editorial reviews, while they can be biased, are usually based on real world experience of the tires, where they face the multitude of variables that make a tire good (or not good) in real world circumstances. There is the possibility tires will not be tested on equal terms (i.e. Tire A was tested after a rain storm while Tire B was tested in blistering hot dry conditions) but I think having many testers doing many tests over a long period of time would mitigate these inconsistencies.
I also disagree with the analysis that 3% difference in tire rolling resistance will directly translate into 3% faster climb or race time (off road that is). There are just too many other variables. If that where the case, every XC racer would be riding hard rubber slick's...but other factors such as rear tire traction, braking bite, cornering traction, etc. all have a BIG effect on the overall performance. i.e. On a climb you could run the lowest resistance tire in the world, but if you are losing 1/16'th of a spin of the rear wheel every pedal stroke due to poor traction, you are not going to get that 3% gain from rolling resistance, compared to an equal rider with slower rolling tires, who loses less traction on each pedal stroke.
I read the MBA tire review today at lunch, while there may have been some brand bias (I don't really see it though, there where high and low rated tires from most of the brands, the top two may be suspect?) deffiantly the biggest bias is towards dry south-west riding conditions. They never took into consideration performance in wet, muddy, slippery conditions...making the review less relevant to me, riding in the North-West, where wet riding performance is always a consideration!
You have to take any published review with a grain of salt. Read the review, apply some common sense, your own past experiences, see what has and has not worked for others riding the same trails as you, and make an informed buying decision on your next set of tires. Or, you could always use the trial and error method of finding the best tire for you...but I learned that can get pricy, and sometimes painful. ;-)
sh0rty