would say Glasgow and Edinburgh are about equal as the best (though in my experience you need higher grades to get into Glasgow), with Aberdeen not too far behind, and as a law school Strathclyde seems to be fairly well respected as well.
Just thought I should add, i know Strathcylde is definitely well respected as a law school within the Glasgow area from work experience with lawyers etc but have no clue about whether it is in the rest of Scotland :P From a friend who did a bit of law at Strathclyde, the teaching style was fairly different to Glasgow, so it may be worth looking into that sort of thing for your unis, as there really isn't much between the top ones.