For health benefits, it's better for you to eat the ingredients whole rather than pureed (liquid passes through the body faster so less nutrients are absorbed). But anything is better than soda!

I've been "juicing" for some time now and find the process very beneficial. While I agree with C-P that eating a cucumber is more beneficial than juicing one, I can't possibly eat all of the foods necessary in a day to get the nutrients out of the 130oz or so of juice that I consume. It is not meant to replace eating whole foods, but to "reboot" your system after consuming processed, toxic foods for months or years. Plus, I'll do anything I can to keep my body away from the ills of pill-dispensing western medicine.  Good luck. PM me with questions and/or results. (The first link is a documentary style intro to juicing.)

Heard that they can change the taste of your spunk (for the better).

When I tried juicing my bacon cheeseburger, it did not turn out well.