I used to live in Esslemont House (which is the same as Hector Boece = the Ghetto, just looking less old), I loved it there because I had awesome flatmates. Yes it is not very big, one fridge for 6 people is a little tight, the kitchen has 4 chairs only... But it's really not bad (the people you're living with make the flat, not the flat itself IMO).
I'd say that the best quality/price flat is North Court, it looks nicer than most other halls, bigger rooms, a lot less expensive than New Carnegie Court (you do get your own private bathroom in New Carnegie , but is it really worth the cost? I'm not convinced...)
Now for the self-catered, I'd say go for the ones on campus (Crombie/Johnston), the ones at Hillhead (Adam Smith, Wavel House, etc.) don't look great (I've only been once or twice for parties, so don't remember much...) it looks all the same inside, I got lost so many times in just one evening, I couldn't find the way out :/
I know Johnston quite well as my boyfriend was staying there, there are shower rooms in the corridors (there's 2 on each floor) and in some blocks there's only a bath, no shower... But you can easily go to another block as there are SOME showers in other blocks (you've got to travel through the buildings with your towel and shower kit though...). I've heard that Crombie is better, but I haven't actualy been in it.
I hope that helped a little, just pointing out a few facts about the different accommodations
Edit: I forgot to mention, where I was staying (Esslemont), for some reason the heater would stop from midnight to 6 am in the whole building, I don't know if that happens in all the accommodations or only the cheap ones, but it was sometimes quite cold at night...