As someone who regularly visits Ulster and lives in Scotland i am going to have to disagree whole heartedly. If we look at the towns and cities of both there is nice areas, but there is also the exact same issues you find in any other metropolitan area. Same with North Wales, Rhyl, Prestatyn, Bangor and Holyhead spring to mind.
I do agree that if you look at some of the more romanticized cities of Europe, slums have indeed been normalized. I recently had to attend Paris and was shocked to find shanty towns up and down the main roads, place was pure filth.