Pros
There are some deals/discounts you get for other stores (that aren't Primark) or restaurants. You get 15% staff discount (although I think it should be more) Interacting with different people all day definitely helps you as you learn how to handle different interactions. I can't really think of any pros that are specific to working in Primark to be honest, it's the same as any old retail job. Work-Life balance is fine, once I leave work I don't think about it until my next shift.
Cons
Management of staff could be better - at the end of the day, managers will complain that recovery is slow or not done, but this could easily be tackled if they put more colleagues onto each table so that more tables are recovered, rather than having every table half-recovered. In addition to my previous point, they give one person too many areas to look after which is unfair. Having to book holidays months in advance and all at once is very annoying especially since you don't know what plans are coming up in between. I don't know about the other branches, but the customers in Ilford are especially annoying, I guess a pro you could take from this is learning patience.