YES, my wife has been a diamond tier member for quite a few years now, and it does do some wonderful things. Last year the flew us to Reno, all on them. we've gotten that same offer this year, but were unable to take advantage.
Last evening I qualfied for Diamond status for the first time, we are looking forward to comparing offers for me and offers for my wife (the long standing member) to see if there is any level differances. Could be very interesting!