Limerick is a funny place. I remember once flying to Shannon Airport, then taking a cab to my Travellodge which was up on a hill outside a city. I walked down into town, took me about an hour. Then I asked some stranger:"Is this the town Limerick or Shannon?", because I really didn't know. She looked at me like I'm from Mars and said in some weird accent:"This is Limerick". Apparently there is no city called Shannon, it's only the airport!
But anyway, I thought it was quite a nice town and never felt dangerous.