What top end Android smartphone can be compared with Lumia 1520 and iPhone 5S?
Reliable in terms of hardware build quality
Reliable in terms of signal quality
Reliable in terms of software stability
Comment from a young adult who meets lots of other young ones is that he will never buy a Samsung S5 or K Zoom, as there are 'unreliable'.
What is truth and what is biased perception?
The truth is Samsung do run a modified version of Android, Eg, new Androids use on screen keys, on the Galaxy s5 you still see physical keys, even the layout of certain apps is different, eg the Samsung keys give you (back, home, long press for switching between open apps, options, long press for search, ) with normal android you only have (back, home, switch between open apps ) there are even modifications to the notification tray, such as scroll system toogles such as wifi, even with the option to edit, normal Android does not have all that. It is these modifications or changes that one could argue make Samsung prone to bugs especially with 3rd party apps you download from Google Play .
Ive owned an S2 , after 2 years, tons of issues but great ease of use, hence the extra shortcuts mentioned above. But the worst about the Samsung galaxies is the SAMOLED display's, you will encounter colour burnins, ghosting over time. Say 2 years, you will see ghosting on a white screen.
You want quality such as a well built, solid device thats as hard as a rock when you squeeze it? opt for Sony. My advice, Go for something as close to pure Android as possible, (no off screen keys, no fancy user interface or animations ) why Sony, very close to pure Android, brilliant build quality that is equal to the iPhone 5S. (as long as you don't buy the cheapest Sony Xperia you can find, don't get anything cheaper than the Xperia m. (i got one prepaid and its brilliant)
I should note that the camera isn't so great, but reliability, stability, consistency and the best build quality possible is all there. Brilliant battery life too.