I prefer polycabornate back covers over metal and glass. I could not care less about what tech journalists describe as premium design. Let's discuss why.
1. Most obviously: User-replaceable batteries!
It is far easier to build a mobile phone with the freedom of user-replaceable battery, allowing me the freedom to wake up every day at 100% charge and use fast charging without wasting a second worrying about battery aging.
Also, I hate power saving mode. Why would I deliberately want to limit the processing speed of my phone all the time? I only wish to use power saving mode when I am actually low on battery charge, not to extend life span. Why? Because batteries are supposed to be replaceable.
I could spend a long time describing the benefits of replaceable batteries, but conveniently, it has already been done for me.
Ask yourself: Which did you pay attention to more often since you bought your mobile phone? its premium design or low battery?
And for those who now scream “WATER RESISTANCE!!!!”, please read this section of the linked article.
As described there, the water resistance of several non-replaceable battery phones, such as the IP58-rated Sony Xperia Z2 has been proven unreliable by multiple reviews (dead after minutes submerged), despite of its sealed battery! At the same time, the Galaxy S5 (replaceable battery) survived an hour in a washing machine and six hours in a lake (see sources in that article).
2. Robustness
Glass can crack and can get soiled, metal can visibly scratch and bend (do I need to remind anyone of #bendgate? I guess not.), while matte polycarbonate has none of these weaknesses.
Metal and glass is also insanely slippery, see HTC One M8.
3. No compromises
Metal also interferes with signal strength and wireless charging. Polycarbonate has none of these weaknesses!
4. Phone cases
I use my phone with a kick stand phone case like this.
I have observed many Apple users also using mobile phone cases. Why would they care about the material of their phone's back cover, if they cover it up with a phone case anyway?!
If you disagree on anything, please comment. I would be happy to have a civil discussion about it.
