you cannot possibly compare what hilton does to points vs spg or hyatt. The latter two probably maintained the same value over the last few years with very few adjustments (the linked bloody murder scream by a blogger over 2 - two! - properties going up is indicative of how unusual that is)... Hilton on the other hand seems to devalue at 10% annual rate.. we went from being 1c pt just a few years back to less than half cent/pt...