As I reported last month, the Hilton HHonors program underwent a serious devaluation on March 28. I've updated the website with an updated award redemption chart and point density analysis. In summary, redemptions for top-tier hotels have become about twice as difficult to earn through spending on paid Hilton hotel stays. While still easier to earn than Starwood top-tier redemptions, the difference in point density between the two programs' top-tier points redemptions has definitely narrowed, to Hilton's disadvantage.
One side benefit of the Hilton devaluation is that their introduction of seasonal pricing at some properties has caused them to develop an extremely useful tool for viewing year-round pricing at their properties worldwide. The Points Pricing tool allows to you search by city and view all the Hilton properties in that city, and each properties standard room award price by month. This makes it easy to see how the award pricing at different properties varies throughout the year. Here a search for Portland, Oregon, shows how some properties jump in price between June and July: