Which one do you prefer  and tell me, why?

of course there are pros and cons for both, and had Adobe not changed to subscription
business model, I don't think many would even ask that question.

As Affinity Photo is the new kid on the block, less than 1% of the resources are available
for it in terms of books, tutorials, plug-ins and the like. There is an entire industry of support
for Photoshop (example, Kelby empire) will any other program ever have that? Since Affinity
has no legacy to support, the program itself, is less than half the size, and so slightly faster. 

Adobe has done a very good job of seamless, roundtrip editing in its suite of programs,
the workflow of many high volume shooters now is Lightroom-Photoshop-Lightroom.

I think if the use is a few images, Affinity Photo would be fine, my use of PS is close to
20 years, if I were just starting, I don't know what my choice would be. I would have to
find out more about batch processing, actions, layer styles and blend modes, as that is
so deeply ingrained with what I do.

I don't retouch many photos and I'm not good with PS.  At $49.99, I can't go wrong.

Does Affinity Photo have content aware fill?

Edit: IDK but it can read RAW files from my Olympus EM1 mkII.
Yes.

Edit: I've lost my concentration!
Fill Content-Aware vs. Inpainting Fill Tool
https://fstoppers.com/apps/healing-and- … hoto-70201

Affinity because at the time, it was only $39.99 and it did what I needed it to which was minimal tasks.  I've never used Photoshop so I can't really compare functionality or power.

Nowadays, though, I mostly only use Affinity for:
--removing people (or other objects) from the background
--complex skin healing
--slight tummy-tucks.   

Most of my editing is now right off Capture One.

I can't close the program.

When I'm through this evening image I'll logoff.

Last time I checked Affinity Photo (a few months ago) it was still impossible to assign shortcut keys for macros. I don't like software which makes me click too much, I like to use the keyboard and pen at the same time as it makes the whole process much faster. PS has also quite bad usability but at least F-keys work for actions.