I loaded a couple PDF books today and started reading them. A short learning curve discovering dragging magnified page around screen to read a new area of page.
Double tap center of screen magnifies page or removes magnification.
Long tap center of screen pops up bottom menu with magnification adjustment and 90 degree screen rotation.
When reading magnified page, move magnified page beyond left or right screen edge to see page turn arrows or double tap center screen removing magnification then turn page by normal tap on left or right screen edge.
Thanks to touch screen, fast processor and good programming, this a responsive interface. All of this just works very well and with a little practice it becomes instinctive.
Kobo wifi with slow and clumsy PDF interface is not practical.