What are you studying in Limerick? Limerick is not the most exciting city in the world but is still a nice place to live. The university is in a suburb of the city (a wealthy suburb) and is a very impressive campus. Plenty very decent and reasonably cheap accommodation.
People are friendly and you are close to some great secenery. If you are one for big busy city there are better places but if you are into sport the facilities are great, you are close to some great secenery, there is an airport nearby. Once you get to know the place and a few people then it will be great but might be a bit boring for the first couple of weeks. All said it is a pretty decent place to live and yes there are tennis courts although i do not know how many!