Used to live near Bradford. Some of its bad reputation may be deserved (after all there are still some rough areas, some very segregated immigrant communities, some very segregated poor white areas, the riots 20 years ago etc), but in the past couple of decades I think it's been on the up really. For one thing the massive hole in the centre has now been filled in and there's a little shopping centre! Parts of the city centre are quite ok, and most of the city isn't as rough as some people make out. Other positives are the university (people joke about it, but actually has some well respected departments eg peace studies), amazing Pakistani/kashmiri/indian restaurants, the film museum, some very nice old buildings in the centre, and nearby countryside and areas such as Saltaire (a world heritage site!)
Historically Bradford was a wealthy place, but along with many other northern cities Bradford was hit really hard by deindustrialisation and even though it has recovered a bit now, poverty was and is rife. For whatever reason, perhaps location, perhaps proximity to other cities Bradford wasn't able to bounce back as fast as some of the others (eg Bradford is a little bit out of the way and next door to Leeds, which is larger and was more successful at drawing other business in, perhaps business which otherwise might have gone to Bradford).
I don't think Bradford's problems are unique either - plenty of other northern towns and cities have lots of poverty, rough areas, segregated immigrant communities etc. Maybe Bradford is just the most well known of this sort of place because it's larger than some other examples and the race riots really increased its profile.