I've found Facebook to have the best CTR and engagement. Twitter is mostly good for sharing of information and brand-awareness. Instagram is high in engagement, but I've found clickthroughs and link sharing to be tedious and less worth-while
I think that Facebook and twitter has been the best social media platform for me.
I have a lot of different friends and family on different platforms, but I always feel like I have more opportunities to interact with people on Facebook and twitter than anywhere else. It's also one of the most secure platforms, so it's important to me that it has a solid reputation for security.