Spring is a medium low cost carrier (low cost but not as bad as ryanair). Has in the range of 10-20 aircraft, if I were you I would go through an agency for this, well unless your chinese, as they may have some specific changes on there contract and it may be a problem in the future if you cannot speak chinese. Though overall, china is quite a nice place to be, shanghai is a little expensive in comparison to other cities, but very international city.
Hope all goes well...
