In my experience with breeding Discus, they are no more or less hardy than most any other Cichlids, with exceptions being some of the wild varieties that are little removed from their habitat. Buy from a reputable supplier, and preferably local when you can.
My most important suggestions for success-
Bigger is better. Definitely don't keep them in too small of a tank. I would consider a 40 breeder minimum for a pair (although I don't really recommend it) and wouldn't consider anything smaller than a 55 for several pairs. They only "crowd" well in larger setups. Lightly stocked is the best way to go.
Frequent water changes. If you aren't willing to do weekly water changes (at least in the beginning until they are very well established) these aren't necessarily the fish for you.
Filtration- don't get too crazy. Some of the healthiest fish and most prolific breeders rely on basic air driven sponge filters, and they work phenomenally well when well established. HOB and canister filters work well, just keep the flow from being too turbulent. A spraybar with larger holes for more diffuse flow is a great way to get a ton of flow into the tank without disturbing things too much.
Sand substrate, medium tone to darker is better. I don't like gravel or bare bottom for them, as the fish never seemed as comfortable, even in an otherwise bare tank. This may go against other advice from those who keep them, but, well, that's a different opinion
I like a nice heavy, dense substrate if given a choice, as it can easily be vacuumed and is less likely to trap detritus. Pool filter sand in a "natural" color tone looks great, is cheap, and works very well, as does black diamond blasting sand, although it is lighter and a bit harder to vacuum.
High quality food is absolutely essential!
I prefer frozen, but at the bare minimum you would want to use a high quality pellet food. Verified clean live foods such as Daphnia and scuds from a reputable source are also lovely additions to their diet, especially if breeding is your goal.
Lower lighting is often better, at least at first. Heavily planted tanks will work well, but newer fish may not adapt very well at first, and will need the lighting to be adjusted in brightness gradually until they become accustomed to the tank. I'm a big fan of hardscape-only setups with limited use of lower-light plants, such as java fern, in addition to floating plants such as Salvinia, Red root floaters, or even duckweed. This will make the tank relatively low maintenance, while still allowing for nutrient export and cover from the lighting for the fish in times where they want it. Lean some slate or flat stone in the back corners to hide equipment, and often they will commandeer it for an egglaying surface.
Watch the tankmates, fast moving neurotic fish aren't well tolerated, except in very large setups. I found that they did well with medium to larger benign fish such as sailfin mollies, who on their own provided a steady supply of quality live food as they were pretty prolific on their own, and they doubled as algae control
They also seemed to do well with fish such as rainbows, Corydoras, larger barbs/danios, larger tetras, and more mellow loaches, although any Loricariids tended to get picked at incessantly for whatever reason.
I have had excellent success breeding them in very hard/alkaline water in the 7.8~8.2 PH range, and found with the proper care taken to frequent water changes, quality foods, and a minimalist style that they were incredibly prolific fish, with a ton of healthy, fast growing offspring, and minimal loss of eggs before hatching. Individual water parameters aren't important so long as the water itself is quite clean, don't obsess over trying for a specific lower PH unless you are working with finicky strains or wild types.