I'm a 4th year UoN student and I've lived in 3 catered halls throughout my time here. I lived in Rutland, Cavendish and Lincoln. I don't think there is one 'best' hall. It all depends on what you're looking for. If you want quiet living, Lincoln hall has a quiet block. What course are you hoping to study? You may want to live close to where your department is located? What room type are you considering? Some halls may not have certain room types, for example Cavendish is purely en suite. Each hall has its own atmosphere and to be honest it's the people that make the hall. No matter what hall you go into, you're no doubt going to find a group of people that you'll get on really well with. I've met really nice people in each of my years in halls.
I hope this helps, if you have any other questions let me know!