Don't pay extra for your own bathroom, you might as well get used to sharing in first year because otherwise I don't know how you will cope in second and third year. I don't understand why people think that the bathrooms in places such as Rootes are disgusting and unhygienic. You do realise that they get cleaned every weekday and that people living there are generally nice normal people who like a clean toilet as much as you do?
Also where ever you end up the enjoyment you get from the experience will depend entirely on the people your with! You could be lonely with your own toilet or lonely in Rootes because nobody really likes you.