I was forced to start using Discord because some chats I´m in moved to it, but still have to use skype because some other chats stay on it.
By the way, after first week of experience, my opinion is that Discord is far from the miracle which some people make of it. Unfortunately, the newest skype version is step in the wrong direction (at least for me). Basically, I would say both programs can be used, both have have their flaws though.