I use Instagram and I have to say my S5 performance was waaaay better. On the Keyone Instagram is laggy and often freezes or times out. I still love my Keyone though and it is not a deal breaker for me. Hopefully it gets resolved with some updates.
Snapchat actually works a lot better than it does on the PRIV. That's not saying much as there is the occasional lag, but it's definitely usable. Instagram, FB, Twitter, LinkedIn, Messenger, Whatsapp and Telegram all work as normal.
All the social apps work so much better than they did on the priv. Snapchat, facebook and Instagram work better than they did on my dtek60 for some reason. Especially Snapchat.