Book Purchase | The Definitive Guide to DAX

Hi,

I just wanted to get some input before buying, what's the difference between these two (besides the pricing where the other one is cheaper):

The Definitive Guide to DAX on Google Play Store $20

and

The Definitive Guide to DAX on Microsoft Press $40

are both DRM-protected I know Google Play Store version is... I'd like to have the PDF version which I can pass around on my devices: Desktop, Laptop, Phone & Tablet. The EPUB version might be better because it's text-flowing but I'd prefer good old PDF which is the exact print of the paper