Ann,if its for the long haul,then go with Castleknock,spend the money now instead of in 3-5 years from now when you realize that Clonee was always going to have problems with in because of its massive sprawling of estates mixed with a very high number of poorly maintained rental properties.
Walk through any estate there and you can almost spot the rentals at a glance.
Swallowbrook and Castaheaney are very nice estates,Swallowbrook are all 4 beds and its built around a nice green area and has no through traffic as its a cul de sac.A nicely presented/finished house sold there recently for around €190k,which considering they sold for circa 420k at the top of the tiger seems like good value.
As regarding snobbish attitude,funnily enough I have always found that the people that would,have a right,for want of a better word to be snobby are usually the most grounded pleasant people,its the people who have nothing to be snobby about are the ones with the long noses.