Phones running on android are much more easy to sell unlike windows phones.
If until now used only for android, then switch to another operating system such as windows phone very hard.
Windows phone system has worked well on many devices. So bad reviews about it yet. It is much faster and much more efficiently.
To date, there are very popular Android system, Windows Phone or iOS. Each of them has its own drawbacks, but is much more positive, so their customers appreciate.