nope, im not joking, infact very serious. especially when i have close relatives n friends who have suffered the effects of drinking RO water long term (>8yrs).
why remove something which is beneficial to the body (considering on avg a person consumes 2.5L of water each day) ? imagine the amount of minerals lost.
fyi some minerals which are hard to be obtained from food and which can be easily obtained from drinking water.
judging by an avg msian's diet...i wonder how much vege and fruits we consume each day? 5 servings? not even close!! lol
"Which other filtration method won't able to do it!"
you obviously havent done your research

information on the internet is limitless, explore~.
RO filter mainly obtained through a compressed membrane filter in which if applied with high pressure would get damaged. Therefore most RO filter have a storage tank to store filtered water as the filtration process is very very slow. I have personally "saw" open all the filters in an RO unit and it was quite a discovery =D
i wont point my finger at anyone who have bought an RO filter, but just advice not to if have a choice. Reason is because Not many filters out there can effectively filter away most all contaminants while leaving the good stuff behind. Therefore the safest route would be RO.
But if one HAS the choice and knowledge on which is the best filter, why go for RO? get what i mean?

sorry if i offended anyone (especially RO users). but im merely sharing the truth.