Well, I can highly recommend Ruislip as a great place for young families. I grew up here and am now back living here with our young family, I definitely consider it home.
Now, I am not very familiar with Ealing, I only know it a little. My Mum grew up in Ealing but that was a long time ago! Ealing of course is closer to London, that is obvious, and hopefully someone from Ealing will be able to give you a balanced view.
Ruislip is a good family friendly area, decent amenities, the High Street has what you need and there's a good supermarket (Waitrose), we are registered with an excellent medical centre, good transport connections (tube, bus and Chiltern rail), lots of open spaces (woods, Lido, park, playing fields). By all accounts the schools are decent (my kids are in private so can't comment specifically). The most sought after part of Ruislip is North Ruislip.
What are you after specifically in terms of house (type, budget) and schools (state? faith? private?)? Then those of us from the area can elaborate a but more.
Also worth considering Northwood, Pinner, Ickenham, Eastcote - all nice areas in the vicinity.