Bluetooth on the Nexus 5 under Sailfish is very unreliable. It often takes several on/off toggles to work, and will usually stop working again after a few hours to a day and require a restart to work again.

Additionally, the kernel that the OnePlus X uses allows it to wake from sleep with a double-tap on the screen, like a real Jolla. Nexus 5 cannot do this as turning on its touch input requires the screen to be awake too.

Also, if you've used an N9 before - the OPX has what was one of the N9's best features, an OLED screen.