Let's not forget Discord is still pretty young in terms of software.
It doesn't have the years of development behind it that TS/Ventrilo has but already beats them for the general gaming communication tool even if there may be more voice options in TS.
Imo in 6-12 months they will have tools that will surpass TS if they carry on updating at the same rate.
I never really liked TS's default interface, Discord seems way more simple.
...i sound like a massive fan boy... deal with it