I've been reading this with interest as we are moving out to HK at the end of the month with our nearly 6 months old baby.
We've just spent a week in HK (my first visit) and I was pleasantly surprised. I thought it was no busier than central London with much cheaper and quicker public transport and taxis. A big plus was that the locals seem to love babies, so our little one got lots of friendly attention.
We lived in London for 7 years and currently live in a small village in the south of England where I am reliant on car to get anywhere, taxis are either impossible to find or very expensive and there is only 1 bus a day. HK has much more available transport.
I'm not overly concerned about the schools as we should be back before she's school age, but we'll try to get her name down just in case.
Finally the facilities available in HK accommodation are fantastic compared to UK (depending on budget). Many complexes have indoor and outdoor pools, playground, gym, shuttle buses, etc. I have to drive 20mins for a pool at the moment. There are also fabulous beaches and countryside I can't wait to explore in HK.
One more thing, I don't know if it's just me, but I didn't notice loads of pigeons in HK - that's a definite plus over London!
If you get a good relocation package I would definitely go for it.