This brings an added advantage to both the .NET developers and DB developers community. But I see it more advantageous to the .NET community, as SSMS has not done the same level of feature addition as VSTS team. If you go thru the feature list, you would find that entire toolset of DB Pro (Data Dude) is available now in VSTS 2010, but the same tools are more required for folks who work with SSMS, and the same is not available in SSMS. For example the "Compare Schema" feature of DB Pro/Data Dude is available in VSTS 2010 now but as a DB professional I would like it to be available is SSMS as I need to use it more often from there, than from VSTS. An almost full fledged query editor like the one we have in SSMS, is available right from VSTS. But the diagramming capabilities in SSMS are still not as strong as the ones availalbe in VSTS 2010.
As per my opinion, VSTS team has done a great job of fertilizing their platform by borrowing features from SSMS or SMO, but SSMS team has still got a great scope of improvement when compared to VSTS 2010. You can download Visual Studio 2010 RC from here.