To be honest it depends a little bit on the juice but a general rule fruits and vegetables are best for you when consumed whole. Many fruit juices on the market are pasturised and can have an effect on the nutrients, some fruit juices are also processed to remove the pulp which also removes the majority of the fibre. Clear apple juice for example is almost devoid of any fibre and can be higher in sugar than coke believe it or not (minute maid 100% apple juice is 65g sugar per 1 litre to coke's 63g per litre) Quite often the skin is removed from processed fruit juices as well and in many cases the skin is reputed to be one of the most beneficial parts of the fruit, offering health benefits such as reducing your risk of cancer.
To be honest if you are thinking of your health you should really understand that fruit contains sugar, it also contains many vitamins and nutrients sure, but eating any kind of sugar in large quantities is generally not good for you, even if it is natural, unprocessed sugar found in whole fruit. Much better is to eat a larger portion of vegetables and a smaller amount of fruit but certainly drinking fruit juices in large quantities is not really recommended.
