They are both equal. The university you got doesn't really matter, especially when it's between two very similarly ranked universities. There is no job you can get into with one that you can't get into with the other. Employers mainly look for a 2:1, good extracurriculars that show leadership, teamwork and communication skills and some work experience. The university is just one part of the recruitment and both Bristol and Durham have the same kind of reputation with employers "not Oxbridge but still pretty good"