MSC or Kirby?

I just graduated from KP in June, and I took a job with MSC. I began training with MSC on Monday, August 11th. That same day, a representative from Kirby Inland Marine called me and offered me a slot in their tug pilot training program. I am now debating whether I should stay with MSC or leave and take the offer from Kirby. I like the offer from Kirby, but I have two major reservations about leaving MSC:

  1. If I leave now, I believe that MSC will unofficially blacklist me, making it impossible for me to be hired by them again.

  2. I’ve never worked on a tug before, so I have no idea if I would enjoy it. I don’t want to flake on MSC for something I’m not certain about.

Does anyone have any suggestions? Any and all advice would be greatly appreciated. Thanks for your help.