Let me start off by mentioning that I'm not a doctor, a nutritionist, nor do I have any formal training in either the medical or dietary fields. Just a guy who has read a lot of peer-reviewed literature on these subjects, done quite a bit of juicing, and is very interested in optimizing my eating plans to achieve a healthy, long life.
I've been using juice extractors off and on for 20 years now, and have owned four or five of them during this span. While the benefits of drinking three pounds of vegetables in a single glass are undeniable, I've found the prep, processing, and clean-up become burdensome over time and inevitably discourage me from continuing juicing for any period longer than a few months at a stretch. Just recently, I've pulled my blender out of our cupboard and have started blending my fruits and veggies instead of extracting juice from them. I must say - the process is much quicker, and the resulting beverages are delicious. Here's some benefits of blending in more detail:
Time Saver - Preparation - The biggest advantage to me of extracting vs blending is prep, processing, and clean-up. Both juicing and blending require fruits and veggies to be washed thoroughly, but ordinarily you’re forced to chop them up into smaller pieces for the juice extractor. This adds prep time, especially when you consider the sheer number of items going into the juice you’re preparing. A typical 12-14 ounce glass of my favorite fruit and vegetable juice uses six large carrots, half a melon, several hand-fulls of spinach, and two apples. Contrast that with an orange, an apple, two bananas, spinach, and a scoop of protein powder for the blended drinks, or smoothies.
Time Saver, processing - Once washed, all the fruits and veggies are placed into the blender pitcher and they're ready to go. Add some ice too, if you'd like. I found that ice helps keep the froth level down in blended drinks. Simply put the lid on, turn the blender power on, and let it whirl. I typically blend for 60 seconds so to make certain there are as few chunks as possible. I'll soon invest in a Blendtec blender, as my research has shown this is slightly better, and certainly a little cheaper than the Vitamix. More on this in another post.
Time Saver, Cleanup - Simply give the blender pitcher and lid a rinse under warm water, put a teaspoon of dish detergent into the pitcher and fill it 1/3 full of warm water and then place it back on the base. Turn the blender on and let it spin for 30 seconds, then rinse the pitcher and lid again and you're done. Contrast this with the cleanup associated with a juice extractor. The extractor must be disassembled and each piece rinsed individually. In addition, the pulp basket must be cleaned out, which usually involves a brush of some kind. Of course the pulp (fiber) makes pretty good garden mulch, so there's no real waste in that sense.
Fiber - Fiber is a vital, often-overlooked component of everyones' diet. Aside from fiber's well-known roles in digestion, it's also useful in slowing down the absorption of dietary sugars into the bloodstream. Abrupt concentrations of sugar cause insulin spikes and these are usually followed by feelings of hunger soon after. Where extracted juices have high-concentrations of sugar with no fiber to regulate their absorption, blended smoothies have plenty of fiber, which does not cause dramatic spikes in insulin, and the additional bulk helps you feel full and stay satisfied longer.
Storage - Blended drinks tend to keep longer in the refrigerator than extracted juices. I've read that extracted juices should only be stored up to 24 hours, and my experimentation confirms this. Blended juices can be kept in an air-tight container for up to three days, although I'd not go beyond two, just to play it safe.
Cost - Blended juices contain all the fiber of the original fruit or vegetable, so they yield far more juice than the same amount of fruit or veggies would if you were to run them through an extractor. If you make the switch to blended juices, you'll save money on produce. Don't use this as an argument against extracting though. The benefits of getting enough produce in your body far outweigh cost considerations. Buy as many fruits and veggies as you need for optimal health, and then do the math as far as which method you'll use to consume them. 
Lastly, before you ditch your juice extractor, consider what you're using either device for. If you get plenty of fruits and veggies in your diet in a normal day, blending may be the better choice. If your sole source of fruits and veggies is going to be in your extracted juice, then don’t give that up for blending. And if you have plenty of time, and don't consider clean-up a chore, you might do well to combine extracting and blending. Since extrators don't deal well with bananas or oranges, use the blender for those, and then add your extracted juice into the blender for a powerful, delicious, and nutrient-dense smoothie that provides fiber as well as concentrated nutrition. 
Chime in by leaving a comment. I'd like to hear what you're thoughts are on this.