known >
-centurion is better than platinum
-ML+3 is better than ML+2
"allegedly" >
-centurion = ML+3
-platinum = ML+2
-citi amex chairman > centurion
if you care about concierge more than things like FHR/lounges/domestic 2for1/E0 awards/etc, id suggest going with ML+ if you are going to meet the spending thresholds for +2/+3. +3 is $50K/yr IIRC, dont recall what +2 is.