YOUR decision
Congrats!! Good "problem" to have.
All I would say is, what's right for one person isn't necessarily right for someone else. Make your decision based on what's right for YOU (not what someone on this board thinks you should do).
I had somewhat of a similar situation....hired by SWA, then subsequently offered interview with UPS. Declined the UPS interview knowing SWA was where I really wanted to be. Didn't want to waste their/my time.
Good luck. I know there are many out there that would kill just to have a shot at ONE of these great companies.