On a recent trip to Hawaii, I used the Rough guide to the Big Island - I went to Morocco many years ago with a RG and found it quite good. But the Hawaii one was a true disappointment. First, it was really thin on the ground, providing little useful information that wasn't readily available from the average hotel - with the exception of the history section which was relatively well written. For getting off the beaten track it was entirely useless, whcih ws all the more problematic in a place such as Hawaii where there is practically no independent tourist information available. But what was in someways even more annoying was the distorted perspective that pervaded the book - a perspective that was clearly the author's own and reflected an attitude to travelling that was anything but rough. Driving to the volcano, which certainly is a unique experience but is for the most part an undramatic drive along a well-maintained wide paved road, is described in words that conjures up a hellish landscape of fire and brimstone. Similarly, a walk down the Waimea Valley - steep, but an easy walk for any fit hiker - is described in language reminiscent of ascending a Himalyan peak. There were numerous similar examples that I can't mention. Such overexaggeration seems more fit for a Frommer's or Michelin guide book, but giving RG the benefit of doubt I went to the website to read the other destination descriptions. I figured a good reality check was to see the description of my own country - Sweden - and was astounded to find not only the same extremely subjective and biased opinions, studded with considerable errors of fact. (E.g. the Stockholm archipelago has no equivalent anywhere - virtually identical ones exist not only all along the southern Swedish coast, but also in Finland and Canada; Sweden allegedly has the least varied geography in Scandinavia, although a quick look at a map would suggest Denmark and Finland, which lack mountains, would vye for that position; the national parks in northern Sweden are described as remote, untouched and dangerous, when most of them are crisscrossed by well-marked trails used by families and even cyclists (!)). Now this may not seem striking, but there were many, many similar slight twists of the facts or clear misrepresentations. I suspect that other readers could spot similar erroneuos or biased descriptions of destinations they know well.
It could of course be that the Hawaii and Sweden guides are just rare errors. But I think it more likely that they reflect a more general RG policy of allowing individual writers to permit their personal views and prejudices to overshadow the content of their writing (even when it is clear that the writers have a clear dislike for their allotted country), and a flagrant lack of double checking the facts. Even LP guide books, which can sometimes be too overpowered by their author's biases, are much better at keeping an evenhanded view and are much more accurate with the facts.
I continue to use the RG online guide as a quick introduction to a region. But whenever I need to buy a guidebook, I quickly turn elsewhere these days for a more objective, unbiased and less error-ridden guide to my destinations.