Ipad pro vs tablets is basically pen vs pencil.
I'm a developer who can't draw. I've used palm, wacom tablets, samsung pen and a window "tablet" from 2008. I've used it to draw stick figures, notes and maybe a math equation or two.
I've played around with an Ipad pro and watched a ux designer use one.
Assuming you can actually draw, Ipad pro seems to be much better. It has a different feel than a regular stylus, it seems easier to shade and sketch than a regular stylus.
While it seems nice, it seems to be a niche devices.