I just upgraded from Nexus 5 to Galaxy s6 and so far not much impressed from my new phone. Except for the camera, there's absolutely no reason to buy a presumably better phone. I was in love with my Nexus 5, the best package ever as regards a phone.
If someone is considering buying a new phone, go for Nexus 5x its a great mobile in my opinion The NeXus series is the best phones for Hi-end performance
I'm a NeXus Fan.