Originally Posted by
Chiller3333
Which one's worthier than is as simple as comparing the difference in cost, factoring in the miles you'd earn on the revenue ticket and compare that to the miles needed for the upgrade.
And not forget to apply the lottery factor X which is the likelihood of the requested upgrade to clear. And what X is? I guess nobody knows for sure....
The best rule is: If you want to travel in a specific class of service, buy (be it with cash or miles) a ticket for that cabin class and do not rely on upgrades.