Welcome to Simply! I prefer a drilled tank with a sump filtration system, that way everything is hidden and I can use as much filter media as I want. As an added bonus, the main tank's water level stays the same, only the level in the sump drops (due to evaporation).
It's really not too difficult to care for discus (assuming you start with good stock), and there are many filtration options that a lot of members use: HOBs, canisters, and even sponge filters. It really comes down to what you prefer, how your tank will be set up, and how you will use the filter, combined with other cleaning methods, to keep your tank healthy.