I have last month's C/D review of the Eclipse with me; the highs are "power top stows tidily, refined road manners, torquey and musical V-6."
Their 330 did break down, but that doesn't speak for every other problem-free 3-series. Apart from long-term tets, reliability is beyond their scope, and it shouldn't be a factor for them, IMO. This goes both ways, too; they shouldn't outright praise Toyota reliability just because it's a Toyota. And, not that it matters, but actually the BMW is larger than both the Audi and Lexus inside; and performance numbers can only tell half the story.
Actually, CR "recommends" the new Impala because of the past model's (excellent) reliability.
Re: the CTS, if that's the case, it seems more like poor fact-checking and poor knowledge of the subject than intentional bias. Either way, errors like these hurt credibility, and CR should make a greater effort to explain such limitations and corrections to their readers.
Nitpicking aside, all magazines with a consumer base need to be overhauled, IMO. As far as bias, it seems like most find it necessary to explain the historical-established-status-quo-background of the product before the actual driving/design characteristics, though personally, I think it's "a good thing" in a review. Many "suffer" more from inflated egos and eccentricities than agendas, and ultimately, it's up to the reader. I take everything with a grain of salt, but still enjoy the crudeness of C&D, the artfulness of Top Gear, etc..