Originally Posted by ScGhost0

As an E75K person who was E50K previously, I can say that there isn't a massive difference as yyznomad and Pseudo Nim mentioned. However, the two things I can see that may be valuable depending on your flying habits are the fact that E75K have a higher upgrade priority than E50K, but also that you are guaranteed reservations in the event you absolutely must fly today (with the restriction you must book into full Y fare). For those who do a lot of last minute flying and can afford the full fare Y class, this can be very useful. Other than that, again, there is not a massively noticable difference. Additionally you also get complimentary preferred seats on international flights if in Flex, which is quite nice on those long hauls of both Rouge *shudders* and mainline alike.