Originally Posted by twa777

While this may not be sufficiently important to the OP, on the initial question of "What is the marginal utility from Silver to Gold?" my anecdotal experience has been that Gold (and higher) get significantly better treatment when it comes to IROPS -- from priority in getting space on the next flight out to being provided room at a better hotel if forced to stay overnight due to a mechanical problem.

Of course, if you have trouble-free flying then this may never give you any value; however, when things go wrong (and with flights running very full), it can make a difference in whether you get a flight out later the same day or if it's a day or two later.