Given Google's reliance on core domain authority and displaying outdated PageRank scores, cache date is a much better measure of the authority of a particular page or site than PageRank is.
What Google frequently visits (and spends significant resources to keep updated) is what they consider important. If a site can throw up a bunch of new pages and see them in the index right away that is a much better indication of trust than just the raw PageRank score. Plus the site can recoup its costs much faster than a site stuck in the crawling sandbox.
This is especially important consideration if you are in a news related field, as sites that are quickly indexed rank for the new ideas while they are spreading, and enjoy many self reinforcing links due to automated content and the laziness of journalists, bloggers, and other webmasters.
Jim Boykin has a free tool to check the cache date of a page or site. It will also show how recently other pages linked to from that page have been cached.