The A5 is not as good as the still-operable 5x.
Oh, the battery is probably better, and maybe the camera. But the one thing I had hoped for was a better antenna for the not-so-good bandwidths of my cheap mobile service provider, and in practice it is no improvement. If I want better coverage inside my building I will need to go on a post-pay service plan.
The biggest drawback of the A5 is the age of the operating system[W]. Like most Samsung devices it does not get updates. Samsung dramatically modifies Android to suit its hardware, which is cool in theory. In practice it means they would need to modify every update to Android, which is constantly evolving, to suit every previous phone model Samsung has produced, and they just do not do that. Effectively every Samsung model is orphaned at the version of the OS it was released with.
Mine was released with a rather early version of Android 7. Even shifting to LineageOS[O] it is still running a version of 7.x.
The Nexus came with 6.0. It is now running on the February 9 release of LineageOS which is based on Android 8.1. Sometimes change is good. The ability to change is best.
And, now that I have managed to flash my way up through vendor images to the most current, I get to decide: do I move my sim back to the Nexus? I lose the SD storage chip, but shiny new OS…