UPS Seasonal Driver

I have a question for the 30 yr UPS person. You've been so helpful to so many people I am hoping you could give me some advice. I am being considered for a position at UPS as a Seasonal Driver. I'm also considering a Courier position at Fedex (that one is only part-time) I really like UPS but I am scared that I won't be kept on after the 3 months and then be back to square one. OR should I take the sure thing and go part-time for Fedex which offers benefits. I'm very torn, because I would really rather go with UPS. What's your opionion?