Hello Dave Navarro,
Expression Blend 3 handles our controls pretty well. There are occasional bugs and inconsistencies and we are working on resolving those as soon as we see them or get reports from the community. That being said you should keep in mind that most but not all controls have blend support at the current stage. With the new features of Blend 3 and Silverlight 3 it is almost possible to code a simple app entirely in Blend, though VS is still superior when it comes to coding.You can have one and the same solution open in both environments letting you take the best from worlds just by ALT+TAB-ing. Blend 3 not has a support for TFS which although not as rich as the VS one lets you perform most of the basic tasks. I would recommend you downloading a trial and give it a go. Also I would like to point you to this article
for some further reading and overview of how our controls behave in Blend.
the Telerik team