The worst I saw was when I was teaching in China a few months ago, during the night I could do 4MB/s but during the day there was no connexion at all, everyone was downloading everything available on Internet leaving absolutely no bandwidth at all... Here at least it's usable
They don't really throttle the connection, it's just that all connection going outside of China goes through a big proxy which then blocks everything they don't want you to see (you can easily go over it though, just prepare a VPN server in your country and make all your data go through it ).
Yep, it isn't a magic bullet but should help ease things. You might also want to consider blocking P2P stuff and video sites (yea it is horrible but if all you have is 3mbps for hundreds of students it is better than having no Internet at all).