In terms of QOL it's really a function of your "Total or Hard Line Bidding Power"

Your Effective Seat Seniority / # of Total or # of Hard Lines in Your Bid Pack

(....Total for a guy who doesn't mind Reserve or VTOs....Hard lines for those who only like bidding "known trips")

Looking or comparing simple, raw seat seniority is not an accurate assessment.

With a shrinking bid back (...like the 727 for the past 5 years), one may have relatively medium "raw" or "effective" seat seniority (because their seat may be overmanned), but much lower "bidding power" because the # of lines in their bidpack are so small.

I think the Airbus and 727 have suffered from this the most during the past few years.