While it is true that DNS will only improve the "Looking for..." times, it is important to consider how many web sites have graphics (ads, etc) that are hosted on multiple DNS addresses, and therefore, faster DNS response would improve those load times since it can resolve and get to that content faster. Moreover, different DNS servers often take advantage of different routes and cache servers (such as Akamai hosted sites) than other DNS servers, so when you're routed to faster servers, you would see faster downloads.
I wouldn't trust it as an end-all-be-all solution, but it can help some people often enough to be worth trying out.
