If you have to ask then...
In terms of Sino Jet I have heard good and bad things it will really depend allot on the end client. Management companies basically get dictated to some extent on how the clients wants to treat the crew. I have had people have good experiences with Sino and some with average. No one I know has had a terrible experience so that might speak of the overall experience.
In terms of Hong Kong and Asia for that matter It's a bit of a secret society with different conditions and pay all over the shop.
Just remember to compare apples with apples.
Commuting/Living in China:
Most people prefer to commute from Hong Kong due to a number of reasons (Life style, family).
Commuting contracts from Europe or anywhere else for that matter are becoming rare (shock horror, you can actually live comfortably by moving away from Europe).
Also many contracts are not rotation anymore or if they are they quickly stop when the owner doesn't fly much after the initial purchase. You will likely have no real schedule either.
Salary:
When looking at the package always compare it to USD
Many contracts now include housing in the total package and don't have it as an allowance (Singapore, Thailand, Indonesia included) So always always for about $4-5K USD a month for housing.
Schooling is becoming less common too (a good international school is $10-$30K a year depending where you are)
Flights home (hahaha forget it)
Here are some ball park figures, given I have seen some unsuspecting people join companies and not realise how expensive the expat lifestyle is and how HK and Asia can chew through that salary. you can add maybe another 10% to these figures for senior roles or being in Hong Kong but are valid for the whole of Asia.
all figures are Captain and inclusive of housing (FO take 60% of these or the lowest number), no doubt there are guys on more but if you are negotiating these are here so you don't get low balled:
L45/C650 $12-16K USD a month
G280/CL605 $16-21K USD a month
GLEX/G550 $17-25K USD a month
G650 $20- 30K USD a month and other crazy numbers
Just remember, you are an expat which means the salary should reflect that. I would recommend going to Hong Kong or Asia first spending at least a week there to see how life is and the expense you have to go to get the same lifestyle you are used to at home.
But overall I have done 6 years and have enjoyed it and has been well worth the time. Just remember its not the same as home and the more complaining you do isn't going to change that. You have to want to come here to enjoy it otherwise you'll be a pain to the entire crew