Kenneth
I guess it's a definition of what brutally honest means.
I haven't seen a review from any music mag concluding something along the lines of "save your money and buy 'competing product' instead" that really says it all.
I can't speak for others, but the odds of seeing a review like that from me are EXTREMELY remote, because as there are more products available for review than could ever be reviewed, I get to choose the products I want to review. Which scenerio is more likely:
"I just saw this really amazing product at NAMM! Man, I'd love to get my hands on that and check it out!"
or...
"I just saw a product at NAMM that doesn't interest me at all, and it looks like it's not all that well-designed. I think I'll spend a month of my life learning everything I can about it!"
Now, of course sometimes I find elements that are disappointing, incomplete, or whatever, and those are noted in the review (e.g., the lack of sophistication with staff view in Sonar

). But there have only been three reviews I've ever written that were total slams of products with no redeeming value. Here's what happened:
Product #1: I sent the review to the manufacturer for fact-check, and was shocked they never replied. That was because they had gone out of business...wasted two pages in the mag.
Product #2: Taken off the market in exchange for not running the review. The product was completely redesigned around my complaints and the changes I suggested, then re-released a few months later.
Product #3: Also taken off the market in exchange for not running the review. I promised to review it again when it was fixed, but it was never really fixed, the new version never came out, and the company went out of business.
Any time I write a review, I'm always concerned that I'll miss some "fatal flaw" due to not having infinite time to find problems, or because I didn't use the product in a particular way that would reveal it. So far (knock on wood) that really hasn't happened. Of course it works the other way too, where I don't want to miss some stellar feature.
Ultimately, the only reason advertisers take out ads is because a magazine has lots of eyeballs. So, the readers always have to come first from an economic standpont. But from a manufacturer and reader standpoint, it makes more sense (given the limited number of pages available) for a review to talk about something that's really cool and interesting. There really aren't very many "bad" products, so the choice is usually between something hot and something sort of average. The hot stuff is more fun to write about, and reviews of those products are more fun to read.