For me, the state and sub-agency control of information about their own parks is what makes it valuable to me. While planning a recent week camping in CO and WY, I learned that most of the aggregated information I was finding from general hiking sites (even stuff like trails.com) was outdated. Surprisingly, the National Forest Service sites ("optimized for IE 6!") contained information accurate to a few weeks.

I'm also a little thrown off by Topiphi's heavy focus on "Permits" on each National Park page. For every park I'm trying, it points me to the "America the Beautiful" annual pass. Sure, while that pass would get me through the entrance gates, there are numerous other one-day, one-week, senior citizen and corporate passes that also given me access to the park. The majority of casual users aren't likely to be looking to buy each family member an $80 NPS annual pass, so I'd like to see more info there.