We love Android for the control it gives to the users. All you need to have is good hardware. App permissions, fragmentation, battery backup are still a concern.
Windows Phone on the other hand has a responsive UI. Offers excellent value for money. Customizability, apps and availability in non Nokia phones should be improved.
iOS offers all that a ‘regular’ user wants. Its very good for those who just want to use a smartphone. Affordability, customization are some aspects that Apple should take care of.