Read the course descriptions carefully. Not just the general blurb about the course but the detailed unit/options for all three years. Which units would you actually choose? Which whole course interests you the most? What extras are available - Year Abroad, optional courses in other Depts? Which course is going to hold your interest and entusiasm for a whole three years of study?
Although you do need to take other things into account, the actual course is the most important thing in making a final choice between two Unis. Dont get hung up on 'prestige' or 'jobs' - this counts for nothing if you get to Uni, realise you hate the course, and either drop out or have three unhappy years stretching ahead of you.