The University of Manchester is one of the top universities in the UK. As we always say on this site, it is the supervisor and the departments reputation you should consider, not the University - there are good departments in bad universities and bad departments in good ones. The most important thing to look for is the Research Assesment Exercise rating (5* is the best).
You should not rely on part time work for financial support. You will not always have time for a second job. Also you should check that you are aloud to work whilst studying in the UK. Nowadays most people are, but you should confirm this before you arrive.