simply discus is a great site. Very friendly, you'll find no rude comments there. From the site i've learned that you don't need to use ro/low pH water for KEEPING discus. That's right - considtency and good water quality is most important. pH 7.8 is find. For BREEDING them, that's a different story. They recomend lower pH.
They are not against planted discus tanks, but feel that for growing out the discus (takes about a year), discus only, bare bottom tanks is the way so the fish can grow to their full potential.
What I found interesting is they know tons about the fish, but less than you would think about water chemistry, and some of them go overboard. Once guy cleaned his sponge filter with bleach/water solution when cleaning the filter. Of course someone pointed out that it wouldn't be nice for the nitrifying bacteria.