There is a lot of anti-juice sentiment currently. These opinions are mostly enunciated by followers of Paleo and Low Carb Diets. Of course, individuals on such diets dislike carbs in general and, not too surprisingly, find the most evil of carbs to be fructose. And what has more fructose than fruit juice, eh? (For more information on the potential problems with overconsumption of fructose, see my links on Fructose and Erectile Dysfunction and How Fructose Sabotages Weight Loss.)
Now the anti-juice folks probably do have a good point: clearly you should not over-consume juice. As you may have read in my link on How Much Fructose is Safe?, most experts do not recomment more than about 50 grams of fructose per day. This is well over what one would normally get from even two 8 oz. glasses of most juices.
However, Tim Ferriss, a well-known time management author and Paleo diet advocate, recently articulated other concerns about juice in a post on AskMen at even lower consumption levels.  His contention was that when he consumed 12 ounces of orange juice per day, his cholesterol, iron and albumin levels increased significantly. Is this possible? Of course, and some of these effects are seen in those who consume large amounts of table sugar (which is half fructose).
Unfortunately, there are a couple of big problems with this and other similar articles. First of all, Tim Ferriss' "study" is not controlled and has a sample size of 1. Beyond that, he just happend to pick one of the three most common sweet juices sold on shelves today, the others being apple and grape juice. All of these juices have admirable properties - apple on memory and orange and grape juice on blood pressure - but with the pulp, fiber and flavonoids removed, they are of debatable value and can be potentially harmful if overconsumed. Even common sense tells asks, "Why consume a lot of sugary juice when I could just eat an orange or apple instead?"
Does this mean, though, that all juices will produce the negative effects that Tim Ferris talks about? Certainly not! First of all, some juices have much lower levels of sugar. 8 oz of orange juice has 28-32 grams of sugar, where juices such as cranberry and/or beetroot juice have only 10-14 grams.
Most importantly, not all fruits are created equal. Pomegranate Juice, as I document in my link, is incredibly powerful and will actually do the opposite of what Tim Ferriss described according to the studies: it will lower cholesterol and blood pressure and increase nitric oxide while its at it. It is so powerful that it will even clean out arteries in some men and improve erectile dysfunction. Read my link on Pomegranate Juice for more information.
Furthermore, cranberry juice is known for its iron chelation powers.  Yes, that's right - cranberry juice will actually remove iron from your system and so much that, in the above study, it can be used as a partial treatment to inhibit E. Coli growth. So one simply cannot generalize about all juices. (Cranberry is also low in fructose and boosts nitric oxide and protects against overgrowth of many bacteria!)
Again, Pomegranate Juice is another example of a juice that should be a bad boy, but is anything but. Although seemingly quite sweet - it has 32 grams of sugars per 8 ounces - it lowers blood pressure, boosts nitric oxide and so on. So, by assuming that all fruit juice will cause problems, is a generalization that simply does not always apply. Many guys struggling with arteriosclerosis and erectile strength issues may be missing one of their strongest allies with this kind of thinking.
Cranberry is no less impressive and actually raises good cholesterol (HDL) according to a couple of studies - see my link on How to Raise HDL for more details. Even more significant is the fact that it combats the TNF-alpha inflammatory response. Anyone who ignores cranberries' superpowers, especially with its low sugar count, is being short-sighted at best. (See my link on How Juice Can Hammer Inflammation.)
Pomegranate and cranberry juice also likely protect against prostate and stomach cancer, respectively, as well. So be cautious about the recent anti-juice atmosphere that currently prevails: you may be missing out on some of nature's most powerful foods.
2) BioFactors, Volume 37(2):121 130, March/April 2011, "Iron chelation by cranberry juice and its impact on Escherichia coli growth"