I have now received my MLIFE packet--which doesn't say all that much about the full system--however, in a sub-sub-(sub) menu on MLIFE.COM, there is a grid showing advantages of the various tiers. Except for one or two items, platinum and gold yield pretty much the same perks--one plus of these is special lines at buffets etc.
Nowhere is the status NOIR mentioned (at least Harrahs acknowledges the existence of SEVEN STARS in printed brochures and elsewhere).
I'll be in LAS this coming weekend and try to get more info from the (Players Club)=MLIFE desk.