Hi there,
I lived in Ballybrack for 5 years and had thought same originally bit rough etc but all yobs that used to be there are now grown up ( I should know I ended up marrying one lad who is fomr there!!) , respectable area and so handy for M50 and shops etc. Moved not too far away now but would recommend area for handiness to beach etc 10 minutes, DART bus on your doorstep, acess to shops, scholls etc. I think it will really be worth looking into it more, Louchlinstown is still a little rough but same will happen over time. Prices are good there too.
HTH