Look, hundreds experience hasn't been mine but I suspect she lived in HK a while ago (geoexpat hasn't been mainstream since 2010), and it's also a matter of different life stages (I only had 4 months of party time in HK before becoming pregnant with DC1). So the following is my experience of living here as a parent and working in banking (as does DH)
HK has changed a lot even in the time I've been here. The expat population has diversified and aged (far fewer 20 something bankers/lawyers now as grad hires are predominantly local), massive crackdown on corporate entertainment post 2008, and HK hasn't been immune to insta culture whereby falling out of bars is no longer in line with one's personal brand . A lot of the millennials I work with are more likely to be heading off to yoga than Lan Kwai Fong after work. The crazy social life is still there if you want it (and the helper culture means you always have babysitting) but most people with young kids don't have crazy party lifestyles and there's plenty of other stuff going on so you can find your tribe. I know as many vegan, tee total trail runners as coke heads (more actually- ha ha). I'd agree that if the only thing standing between you and alcoholism is childcare restrictions, then don't come, but otherwise, you'll have a few more big nights per year than you might have in the UK and a lot more low key dinners with mates where you all look at your watches at 11pm and say "shall we get the bill- got to take the kids to rugby at 7:30".
Marriage graveyard? Not the experience of my circle - the few couples I know who split, split very soon after arriving meaning that maybe they moved for a fresh start and it didn't help. There are also men people who let the whole thing go to their heads and can't keep a check on their white privilege (that twenty five year old hot Chinese chick likes fat balding me for my sparkling personality) and that tends to end badly, but on the whole, I wouldn't say HK is bad for marriages.
School is only intense if you're in the local system but vanishingly few expat children are as you need to commit to that system from birth (or at least pre-school) so that they have the language skills to cope by the time they're six. The preferred British curriculum school, Kellett, is very laid back and inclusive, as is the main IB school network, the ESF franchise. A few of the newer "international" schools have a high intake of local students which can impact educational culture and there are a few other international schools that are hothouses or are academically selective but they're not ones you would probably look at as nationally specific or require mandarin proficiency. The pressure on school places is far less than it was, and critically I forgot about Nord Anglia which is also British Curriculum. That might actually have 3 places as they have recently expanded. It is less popular than Kellett but that's largely as its less established so not the "go to" name. My friends with Dc there are very happy with it. Harrow is also British curriculum, but debentures are eye watering. I would give admissions at Kellett and Nord Anglia a call and just ask them what the situation is.
Work - depends where you're coming from and who you work for. If you're working a regional job so work mainly within your own time zone it's fine but if you're in a global role then the regular evening calls can suck big time. This seems especially true if you work for a US bank in Asia as they seem to consider their time zone "the" time zone that everyone else has to cater for. My company is "centred" in the UK but we also have quite good policies about how early or late "regular" meetings can be for non-UK time zones and all my clients are in Asia.
Sorry- this has turned into an essay - I guess what I'm trying to say is that HK is many things to many people, depending on life stage and lifestyle, just like London or NY. You can live in the thick of it or you can opt for a more laid back life somewhere like Sai Kung or Discovery Bay. You can party every night or you can never go near Lan Kwai Fong/ Soho (pilots and tourists) and still have a really good social life. You can have fun on a variety of budgets but you don't want to be financially disadvantaged by being here so do the math carefully on rent, schools, tax etc.
If possible I would come over and have a look for a few days.