We were the first to announce that Microsoft would be releasing Service Pack 1 for Windows Vista to manufacturing on February 4, 2008; and now we will be the first to announce Microsoft's confirmed schedule for the release of Windows Vista Service Pack 1 to the world. Here's how it's going to work... As we mentioned in our February 4 update, release to manufacturing (RTM) means exactly that - Windows Vista Service Pack 1 is final and is now released for manufacturing, and to the OEMs for integration with their systems. Public upgrades would come later. In April, as it turns out. Today, we were able to lay our hands on their actual release schedule. This is the real deal. Check it out. Here's a quote from the editorial :- Link : ED#81 : Confirmed Schedule Of Microsoft Windows Vista SP1 Releases
Too risky I says I'd rather wait for the official version (tested by other end-users) to come out, just in case