At this point, I've been promoting due to buying character packs to make use of the EXP I get for the classes I'm not using. Mainly doing it for the related challenge, though... think its like 60 promotions? Once I hit that mark, whatever N7 rank I am, is whatever N7 rank I am.
Shame BioWare never made it ...y'know, mean anything.
Playing: ME3, ZoE2 HD, Anarchy Reigns, MGR:R, Sly 4, Borderlands 2 (GOTY 2012) "See You Space Cowboy."