At that point it really does come down to an Aesthetics/Feature showdown.
Do you have a particular colour scheme either in place, or in mind that would benefit from one over the other?
What features do you want? What features don't you care about?
Are you concerned about warrenty?
What are the reliability of the boards?
I agree with you that the ROG board is pretty ugly. All this being said, I literally just bought a new Aorus board for my next build which is currently sitting next to me, so I guess i'd have to throw my hand in with them, purely because it's essentually the ATX version of the board that I got, so feature wise, it's probably the best fit for me.
The Aorus board has more rear USB, which is real nice, but the Asrock board has a combo PS/2 port; which is also pretty nice. So it's a real pick-your-poison decision that all really comes down to a combination of personal preferance and if you really have a specific use case that requires something.
Personally i'd lean towards more relevant features over aesthetics; but that's mainly because I plan my builds around the mobo i choose and not the other way around.