Upgrades advice- though the generic reservations center will tell you that you cannot, under any circumstances, upgrade from the standard room booked with certificates to a suite, if you call the front desk of the individual hotels, they often will allow this.
The numbers have ranged between $150 per night to $400 per night to get a suite.
The $400 upgrade was for a room that lists for $2500 per night, so I should be able to get three nights for $1200 total instead of $7500. A good deal, I think.