I would do what most are saying and just check on line what your comps are. As far as diamond level expectations you get that Bahamas trip, $100 dinner for this year and next, plus when in Vegas you can choose any of the shows on the diamond list which is so so at best.
As a diamond I've always had 5 free nights at any Caesars property, occasional flights to AC or Tahoe never to Vegas. One last thing no resort fees.
