Well, taking the emotion out of the equation, it all comes down to business sense and the bottom line. If I was working at a job I liked doing, and all of a sudden was offered a whole lot more $$$ elsewhere, pretty much doing an identical job, I would take it.
If Saban does take the Alabama job, more power to him. As a Dolphins fan, I'll be pretty disappointed, but I certainly understand and appreciate the business side of the sport.
At any rate, I hope Saban stays with the Dolphins, and continues on his rebuilding plan!