Microsoft/nokia will be using on screen button for low end model, and physical button only for high end model.
this is base on customer feedback, majority of wp users prefer physical button on high end model.
but I think this is all depends on personal preference. I prefer to have physical button because I can have more screen space even though it's not really a significant difference. secondly, I like the windows logo/start button on my phone. it looks cool. one thing I do hope Microsoft can implement is the start button that can act as notification led and blink/glow when there is notification pending to be read.

if Microsoft can cut down the bezel size for those lumia with on screen button, it will look better. example, like the nexus 5. I know some friends who just don't care about specs and OS. they just want a good looking phone. windows phone ady has a good looking and unique UI, all they need to do is make lumia's hardware design super sexy and it will sell.

Lumia 530 use what SIM? Micro SIM?

Are there many people queuing up?