I prefer TS to be very honest I have used Discord and I just find the UI to be just "bleh" Teamspeaks UI yet simple is easy to understand and since it has got a long term following it means the company is less likely to shut down development.
From what I currently understand Discord currently doesn't have a big source of income other than investors. Which means if they cancel then it could all be stopped. Also with TS you own the server the and the information (if you make the server).
I have my own server which took less than 10 mins to do. The server itself is also lightweight and can run on as little as 1vCPU and 1GB of RAM. Licensing wise if you own the server you can easily sign up for an NPL (Non-Profit License) which allows up to a total of 512 clients. No idea how the server is currently hosted but overall TS would have a very small monetary footprint if the server was run using low spec VPS.
Rant over lol Anyway back to TS