Hi Gipilot,
I'm coming from the standpoint of already being in HKG and having been here for long enough not to be hit with the crazy taxes on traditional flat purchases, (ie not boats etc). Life's.... "OK"... for us, as a Kids 'grown and flown' couple. It certainly is waaay! less stressful than commuting, (done it).
Housing ... It certainly has been and remains a great way to make money for us, utilising the Housing Allowance, (genuinely sorry for those who now don't have it) to get going then looking for any more creative opportunities in the roller coaster market, (great fun and I haven't fallen off yet, but I go on the rides with seatbelts). That said, I've done the hard time in a smallish starter flat getting a good bite of a reasonable mortgage paid, it used to be easier, but I believe is still achievable now if you have a little aside. I WOULD NOT come for money alone unless you are going to a). commit for a while, (maybe you'd have the cash to buy in if you sold up?) and b). engineer buying somehow; renting is a game for those who don't care about or need cash for whatever reason. Starting from scratch, I'd advise doing the bank mortgage rules research yourself as they change all the time, (eg the recent 15% stamp duty theft tax has just reduced on first properties), many colleaugues/Ppruners will advise you eagerly, but it's you who'll get caught out and hit with penalties etc, so I guess I'm advising you to listen to advice but treat with caution and double check.
Schools .... look, it's do-able, lots of people do it but don't underestimate the drama involved, plenty of threads around; again, rules change ALL the time.
Pollution .... Standing by to be shutdown but if this was actually a killer then I would assume some sort of affect on average life expectancy?? Check out
https://www.cia.gov/library/publicat.../2102rank.html
NB... HKG No. 8, USA No. 51!! (82% of all statistics are made up on the spot, but at least we can trust the CIA......? ) Donning Tin-Hat
Areas vary, Tung Chung is not great in my experience, but some of the CX marathon runners live and train there so again .... overstated. I asked "The Good Doctor" once and his view was that more of our community had respiratory problems from plant allergies in Oz to local pollution, and as we know he was not a company spokesperson.
Lifestyle.... it's personal. We left a big house, acreage, pool etc and it was a change; but actually, if you embrace a different lifestyle it can be very easy and relaxing. Easy to create a comfy luxurious 'nest' and enjoy the city with all it has to offer. HKG is 3/4 countryside by area, some tough Hiking, great beaches etc. etc. so getting your outdoors fix is easy. Some of the 'HKG is dreadful' brigade may well predominantly just spend their layovers falling up and down Wan Chai in which case I concur. Not that there's anything wrong with that once in a while.
Overall; we came here to make money, we have. We enjoy it here, it's an easy life, but we ID travel a lot to see family. We set the expectation level at never getting another basing so anything else will be good news and a bonus, nearer retirement. Good Luck.