Things to recommend in Shankill:
Active Tidy Towns committee
Public library in a beautiful building
Active GAA for youths, starting up for adults
Shanganagh park, playground, off leash dog area, wooded areas, picnic benches, running tracks, lots of open space
Beach and lovely walk down Quinn's road - blackberries in autumn, horses to feed carrots to....feels like you are in the country
Mountain walk starts in village
Three primary schools - depending on what stage you are at in life this may be of interest
New shopping centre opening early 2015
BBQ centre with decent cafe, lovely bakery, fruit & veg shop
On the doorstep of all Wicklow has to offer
Close to M50 and M11 - helpful for commuting
Dart and not too far from Luas at Cherrywood/Brides Glen
Bus routes into town (145 - also goes to Heuston)
Aircoach for airport
Very settled, a lot of people who live there were raised there
Nice mix, young families, mature couples etc
Creche in Olcovar
Lots of childminders in the area
Parent & toddler group in library and church centres weekly
Close enough to Bray to access all services but not to have to deal with the traffic on a daily basis
Things that could be improved:
Secondary school in the area - one being renovated on Bray road and made co-ed so potential there, although students can travel for school at that stage.
More services in village...eg places to eat, cafe...shopping centre might take care of that
Dart station parking used to be free, now payable. Dart station is a bit of a walk from the village, so if you plan to use it for work walk the distance to see what the journey would be like door to door...also factor in potential drop offs and collections of children.
Luas is so close but so far...proposals in place to build a walkway/cycle path have been mooted, and also in far far future a luas extension may pass through Shankill
Things I would consider regardless:
Where do you work, how would your commute be now and for future jobs
What family life stage are you at, are schools on your radar?
Hallowe'en is coming up, an ideal time to check out what a place is like after dark! Visit both areas day, night, weekend and weekday to get an overall picture.
Would either be near family or if not from Dublin closer than the other for them to visit...becomes important for when you have young children.
Hope this helps, have no info on Lucan apart from the fact that if you tend to travel west a lot it is handy....might have been a draw for us a few years ago but with children we tend to stay put most weekends now and family comes to visit us instead.
Good luck!