Well first off, what are your intentions with the discus?? Strictly show fish or hopes for future breeding stock?? Those two types will have totally different tank environment needs. For just show fish in your home, the planted tank will do fine. Keep the temp up to atleast 82 and the pH can be whatever is necessary for the plants to thrive....as the discus can and will thrive in virtually any pH or water hardness. Water changes for a "show fish" tank can be only 1-2x a week of atleast 30-40% each time. Also, if you decide to do a planted tank, I highly suggest that you invest in semi-adult or full adult discus because younger discus do not do as well in planted tanks...they will become stunted and will become sick easier.
If you would be interested in breeding discus one day, then I HIGHLY suggest to NOT go with a planted tank. Go with a barebottom tank, wet/dry filtration and the temp in the mid to upper 80's (86-88). Water changes would need to be more frequent....daily if at all possible. For future breeders, you want to baby them. You want to keep their tank as clean as possible so they will grow nice and big. Feed them everytime you walk by their tank (yes, even if its 10+ times a day...just feed very little each time). You can start off with discus at the smaller size (2-3") and spend considerably less for them...but the trade off would be more work involved.
One of the most helpful tips I can offer is to buy QUALITY discus. Do not buy discus alone by their apparent apperance. Their overall size, shape, health and vigor must be considered. Try to buy from a local breeder if at all possible. If not possible, then you will have to get them via mail-order. DO NOT buy them from your LFS. LFS discus are generally not healthy and their immune system is compromised...which means they can and will get sick easier. Buy them from a reputable discus dealer/breeder. Also, price is NOT a factor in discus quality here in the US. I can go buy a discus for $20 that is perfectly healthy and has excellent shape and is just all around better than the discus sitting at your LFS for $89. BUT, that does not mean cheap discus are good either.
-Ryan
Orlando Discus