Contract pilot = Why should I give a stuff, as I'm likely to be replaced at some point?
Annual salaried pilot = Hmmm, maybe if I watch my P's and Q's, these folks will get a turboprop, or 'maybe' a jet at some point.
Now that you've thought this over, think ENGINES.
The GTSIO is not fond of ham-fisted pilots, so just maybe the annual salaried guy will watch after 'em just a bit better...and will be 'cheaper' in the long run.