All the water I drink and cook with is RO only then put through a carbon filter for taste and odor. I use it for coffee and it works great. If you were really concerned with the lack of minerals in RO you could get an alkalinity filter which reintroduces certain minerals into the water, my main concern being the purity of the source material and the unknown additions from them. But RO purified water is really the safest thing to drink as we find more and more previously unknown cancerous elements in our ground water from previous industrial activity/irresponsible disposal practices.
There's been a ton of debate about drinking rodi over the years. The common reasons given are thats it's mineral deficient, hypertonic, and it's acidic.
It is slightly more acidic than regular water but soda, any carbonated beverage really is much lower in ph.
The hypertonic argument might hold some water (get it?!) If the stomach lining wasn't semi-permeable not allowing things to pass from the blood to the stomach. It only goes the other direction. Also let's not forget that the second it enters your mouth it will mix with about 1 million particles so it is essentially no longer devoid of soluates. Which I'll talk more about in point 3.
The third Point people make is that it's deficient in minerals and we need minerals to survive. If we drink nothing but Rodi water and did not eat anything then it could eventually (mixing in the mouth) help deplete the body of minerals. but the truth is we get very little of the required minerals from drinking water. As long as you eat a healthy diet (or even a crappy one) it will not ever be a problem.
On an interesting side note pure water will not freeze as water molecules are pretty "stupid" and need a particulate (a nucleation center) to "show them" how to form a crystal.
It isn't my idea. I got the RODI system from Malev's Reef. In his site he suggests to collect the first washing of the membrane to be home used. Instead of sending those ~35 ppm water (in my case) to the DI resin, you use it for drink (coffee in my case). When I finish filling the gallon container, the membrane have been washed and the water coming from it is ~9 ppm. Then I close that tubing and allow the RO water to go to the DI resin.
Every weekend I collect 1-2 Gallons for my coffee. Malev's save it in the refrigerator in small bottles for any use you want. He has pictures or a video, can't remember now.