Discord -Better UI -More organized servers and chat rooms -You can voice call someone and they are free to join(more like a voice channel than a call)
Discord will be adding video chat and screen sharing in the coming updates. I hardly use skype anymore because it's laggy af for me most of the time (tried using it without updating it consistently and with updating it, no dice) and call quality is shit. They're trying too hard to be like other platforms (Facebook, Snapchat etc) and it's just making me dislike it more and more. The only reason I still have it is because some people on there don't use discord like I do. However, many have been switching over and am happy for that. #TeamDiscord
I'm more of a Skype person because with Discord, it was very difficult for my computer to download it for some reason and its doesn't give be alerts like Skype does. I am pretty new to Discord though so I will have to get used to it and toggle with it a bit, but as for now, Skype is better in my eyes!
I really prefer Discord. Being able to create your server and customizing it is really fun, and adding bots for extra functionality is the cherry on top. Even without the servers, you can add friends and call them privately, just like in Skype. Discord is like Skype, but with lots and lots more features.