It straight comes down to preference.
Windows is what I have more experience with. I know it better. That’s what i have. It’s more friendly to open sourced products in my experience. Maybe it is because thats what a lot of nerds use.
OSx is much more straight forward in my opinion. much more stable. (maybe cause it has less hacks written for it then PC’s (cause of the dominance in the consumer market.))
Power wise, either OS will run djing programs just fine. That’ll come down to mostly to ur hardware.
As for the looks. You may not care. I may not care. However you do have the “image” aspect. Looking the part is important, and people associate the shiny glowing apple on the macs with DJs.
Personally when I finally get around to getting a laptop, I’m gonna rock a mac. I like the simple user friendly OS then windows.