I just tried to use mine to upgrade a US - Europe trip. Had a hard time getting both SWU confirmed for me and Mrs mrmik. So I used miles to confirm 2 C tix on the exact routes I wanted. The coach fares were 1200+ and I thought the miles (saver award) was a better option.
I did check for a trip for the fam ((all 4 of us) to Asia and looks like I can confirm 4 tix in coach at $1000 each and use SWU's. Seems like that is a better use.
I'm still trying to decide between the 2 extra swu's of the 25k miles for my award....