Correct me if I'm wrong but as far as I know the only way to see your Vanguard/Crucible/Faction rank and progress to the next rank is by visiting said faction in the tower (bar the little progress update you get after completing a mission/crucible match. It would be super handy if this could be implemented into the options/customisations screen where you can check your bounties and items collected, and where you can see how many marks you currently have. I was thinking a little pop-up menu when you over over your marks would work and be easy to implement.