I heard also that RODI water is so pure it will drain you. I, personally, had an RO system in my old house where I lived for almost all of my life. The guys come and change the membranes about once a year. No one has had any problems due to drinking RO water.
In terms of Fluoride, my father (who is a D.C.) found a somewhat recent study showing little to no positive effects of having it in water UNLESS you do not have your adult teeth. Reading further I saw a story about a town in Colorado (I believe) whom had large amounts of Fluoride in their tap water, thinking it was safe and healthy for the residents. Everyone in the town drinking the tap water suffered from extremely brown teeth, apparently found to be a reaction caused by the large amount of Fluoride in the water.
With all of the crap found in tap water nowadays from chemical plant run-off and certain hospitals and other similar places that flush all medication not being used, I feel it is best to use RO water. These have been indirectly linked to health problems in certain areas (if you live in Rochester no doubt you heard the stories of people living by the Kodak plant).
Just my 2 cents.