In the big picture, fruits are GOOD - the sugar in fruit is fructose, and eaten in reasonable amounts, like almost anything else, it is not harmful.
Barring any medical issues that would require avoiding fruit, the only people on this board who should stay away from certain fruits because of the sugar content are those who are on their strict cutting diets very close to show time.
Fruit juice is less desireable in comparison to the actual fruit because all you get from the fruit juice are SOME of the vitamins/minerals/nutrients, and all of the sugar calories - even more than in one serving of the actual fruit. You also get none of the fiber available in the fruit.
So for the same (or usually MORE) calories in the juice, you get less bang for your buck. In addition, it's liquid and gets digested really quickly, and you are not satisfied for very long. Take apple vs. apple juice. It is very easy to over-consume calories drinking apple juice, but how many people are going to eat more than one standard-sized apple at a time?
1 cup of apple juice - 117 calories, 29g carbs (27 sugar)
1 standard-serving-sized apple - 80 calories, 21g carbs (4g fiber, 16g sugar)
Fruit juice, imo, is best used in small amounts to flavor something else that you're preparing (a shake, a recipe of some kind, etc.). Not as a stand-alone food/beverage.