Actually... What about Glasgow Uni?
I have an offer from them too, and seeing that they have a Comparative Literature course (in which I'm very interested but that Edinburgh does not provide), I'm also considering the idea of going there.
To be honest, that was one of the reasons why I initially took in consideration St Andrews: they have a Comparative Lit program as well, although I know it's been on only for four years. (I'm not even sure how serious a course Comparative Literature is, seeing that it's not very popular). Advice?