Given the two, I'd also say go with the Nubia. I don't find any major problems with Zte phones. Or at least I don't see any problems reported from users on forums and such
Also, I have this friend that mentioned buying an Asus zenfone (not sure which) and the touchscreen and display gave out after a small fall. He brought it to a service center and there was this long line of people getting their screens repaired as well. And these are all different zenfone versions. So...I'm not quite sure about build quality there. Of course, it could be just coincidence but since you have a damn good alternative, I'd say go with that
Also, I have this friend that mentioned buying an Asus zenfone (not sure which) and the touchscreen and display gave out after a small fall. He brought it to a service center and there was this long line of people getting their screens repaired as well. And these are all different zenfone versions. So...I'm not quite sure about build quality there. Of course, it could be just coincidence but since you have a damn good alternative, I'd say go with that