I studied in Aberdeen in 2016, dropped out in 2017, and will return to Aberdeen in September this year too
Aberdeen is a really great uni and they have even just surpassed St Andrews on the Times Higher Education ranking!
I didn't live in Hillhead back then, but a couple of my friends did, and as no one else has replied yet, I thought I'd just tell you what I know.
As far as I know, most buildings are unisex, but when you're applying, you can choose to live on a floor with only people of your gender.
My friends all lived in Fyfe House so I can't comment on the others, but Fyfe House was pretty nice. It's the cheapest I think and the one I'll apply for. The rooms are really spacious and every room has a sink in it. The kitchens are shared (other buildings are catered), and so are the bathrooms. There are several bathrooms per floor. The building also has some common rooms.
I'd definitely bring stuff from home to make the room more comfy
Like pictures of your friends, maybe some small things that you really like, your cushion, etc.
I really like Primark Home however. Primark is about a 40 minute walk from Hillhead (20 minute walk from uni), but you can also take the bus which takes about 15 minutes. There you can buy your own sheets, maybe a nice carpet or blanket, some LED lights, and just general decoration stuff. It's really important that you make your room your own as much as possible, because if you're away from home, you'll want to feel as comfortable as possible
But if you want to know more detail, you can always look on the University of Aberdeen website - they have plenty of information about the accommodation and the different buildings you can choose from.
Can I ask what you're planning to study?