Dennis Bournique has done a great job here of writing a full critical review of the new Skyfire browser for S60. It seems that, despite still being in beta, it's the best for viewing web video, but that there are still some day to day usability problems that need addressing.
Read on in the full article.
And no word about privacy nor security. As with Opera Mini, *ALL* your data is routed through this free webservice. While they state in their statements that they don't share data with third parties, things can get out accidentally. And so might your creditcard number, or other sensitive data, if you pay on some site using Skyfire.
Perhaps I'm paranoid, but I simply do not share logins with any of this kind of proxy-services, be it Opera, Skyfire, or one of those many, many IM-services. I only use native clients on my mobile, which can communicate with the target server in question, and preferably using an encrypted connection.