Although you should be aware that 70 fo's have just been added to the seniority list making 300 total these are the guys who have bided their time for the past 2 years with summer only contracts.
It would be highly unlikely that anyone joining this summer would be kept on at the end of summer 2011.
you should consider this if you are leaving permanent employment for a contract job which may take 2 summers to join the back of a long list!