Agree with Jason Fried’s take on these two platforms.
When I have a few minutes to kill, and my phone is in front of me, I almost always reach for Instagram. I never regret it. I come away feeling the same or better. When I occasionally reach for Twitter, I discover someone’s pissed about something. I often come away feeling worse, feeling anxious, or just generally not feeling great about the world. Twitter actually gives me a negative impression of my friends. I know it’s not Twitter doing it, but it’s happening on Twitter. that’s how Twitter feels to me.
For similar reasons, I don’t use Facebook and almost never check Twitter. I’m not that cool to be on Snapchat or Periscope. But I’m on Instagram all the time. And best way to get in touch is via good old fashioned email: firstname.lastname@example.org.