Originally Posted by
eratosthaenes
Thanks for the great info. And for the answer I wanted to hear. Based on the UAL calculator, ORD-SFO requires 10,000 to 15,000 miles (depending on class of upgrade (again, I am not familiar, as all of AA's planes on that route, and any domestic I have flown have only 2 cabins)). Anyway, it seems a much better deal than $200 for 4 stickers.
For all practical purposes, there is only one level/type of upgrade to be had. You may occasionally be on a 3-cabin plane, but United doesn't allow double upgrades. In other words, on a 2-cabin, you can go from Coach to First. On a 3-cabin, you can go from Coach to Biz OR Biz to First (if you bough Biz).
There's no (regular) way to go from paid Coach to 3-cabin First. Not sure why there would be a difference in the miles required...