Grades, unless they involve comparisons with something else, don't seem particularly informative. So it might be good to encourage grades between one alliance and another (especially on individual attributes or dimensions of the RTW products). However, there may not be enough people with multiple alliance experiences.

As a supplement it might be good to encourage comparisons where people might have more experience with competing (sub)products such as UA vs AA and SQ vs CX-- not just individual carriers but the set of major ones within the alliances.