I keep all 4 with me in my backpack. While they all have phone numbers I only give people my main line, which is on my Note 3. I rotate between them daily. One day I use the Note 3. The next day I'll use the Note 4 and forward calls to it from the Note 3. The next day I'll use the Note Edge, the next I'll use this Alpha. I use Text+ for messaging so folks only have to remember to text one number but I keep the Note 3 powered up and connected to my Pebble in case someone texts my main line.
Complicated I know, but that's how I do it and I enjoy the rotation of devices for now.
♻from the Alpha