I lived in China for 3.5 years in Shenzhen (just left a year ago) and here are my pros and cons
Pros
The international school experience is great for kids- they meet kids from all over. Because of this, but it's not the same pressure on kids to be cool, or to dress the same as their friends for example.
Great holidays traveling around China and Asia in general.
People meet and bond quickly so you can have a fab social life.
You can hire an 'ayi' or auntie to do babysitting, cleaning etc. if that floats your boat. My lovely ayi was invaluable for helping translate with maintenance men, postmen, delivery drivers etc etc.
Cons
The pollution.
Healthcare. I can't comment on HangZhou, but where I lived, there were international clinics but emergency medicine was dire. I lived in fear of an emergency as I did not speak Chinese so would struggle to call an ambulance, which were glorified taxis.
China can be full on. I found there to be quite a culture gap...but it was certainly interesting. I don't miss squat toilets, being elbowed out of the way in crowds and people grabbing my kids to take selfies with them.
I would say, go for it. But I wouldn't necessarily go counting on getting work. Getting a work visa is not straightforward, and it's not somewhere I'd risk working without one.
If I can help you with any questions, please feel free to PM me .