An article from CNET for which they tested the update came to the conclusion that the update was not quite ready for full-screen mode. In their tests, both Hulu and YouTube video content was either choppy or missing video. Their test of full-screen mode also resulted in a crash while exiting the browser.
While the Flash support is a worthwhile feature, I can’t imagine downloading a 130Mb upgrade just to look at poor quality videos through your Playstation. My advice is just watch internet videos on your PC until there is a major improvement in quality.