Higher TDS also means more pass through of minerals be it good minerals or bad. In my opinion a balanced diet + low TDS water is fine as water is not the only source of minerals. The water from my purifier tastes good at 16 PPM shown from a cheap TDS meter. On the other hand, a UV purifier at my cousin's at bangalore with an output of about 140 PPM taste so bad to me. Just my impressions, please correct me if I'm wrong.