I've never kept discus, but I do know that you're looking at LOTS of water changes. The low end seems to be 50% twice a week plus one 80%+ WC on the weekend. I've also heard of folks doing 50% WCs every day.
Also, you're not going to be able to keep aggressive cichlids such as angels with them. Most folks do either a species-only tank or have very non-aggressive fish that can't fit into their mouths, such as corys.