What?You joking?We discuss here smartphone at budget 6000-19,999 and you provide example surface..We discuss here about smartphone and this section microsoft full dead..Now still if nokia come back with android get a market but not able big success...

5.2

In my opinion, mostly it depends of users' desire and users' anatomy. From the one hand most of us wants to have as large screen as it is possible to be able to see more information in good quality on the screen, from the other hand there is some inconvenience in touch screen controls or pocket wearing (to be honest I dont think there is so big "pocket" problem), however there are some functions for comfortable usability aka smart touch & etc, which can eliminate an inconvenience of big screens.
So, as user of m2note I would rather have a larger screen (around 5,7") then smaller screen with comfortable usability. Also I would have to notice that I have no small arm, but sometimes my second arm helps other one to clear RAM in task-manager )).

Perfecto para manos medianas

para mi , 5,2 es tamaño ideal en la mano

5,2

5,2 perfecto

Check complete information.  Microsoft stops working on Lumia
Because they are working in premium which you might not able to afford

Surface phone series.  

Like Microsoft Premium surface book,  and Surface pro 4  :  which won all awards from design,  hardware and performance award

5.2" and above is better!!!

5.2 is perfect mobile  size