Having used MS acrylic for a bunch of project, I have to say that I LOOOVE the program.
Basically MS purchased a company called Creature House, who developed a fantastic vector-based program called Expression. It was on version 3 when MS aquired them. The Creature House team started working for MS to develop Expression into Acrylic as well as to redevelop one of their other applications, Living Cells, which was in beta at the time. Living Cells was a 2D animation package that utilized a lot of the functionality of Expression within it (as well as a lot of other things). When MS aquired Creature House there was a lot of speculation that MS wanted to create some sort of Flash killer using Living Cells technology. To me it looks like they are try to do that as well as take on Macromedia/Adobe in the process by creating, in one fell swoop, a product line to compete with Dreamweaver, Illustrator/Freehand and Flash.
I am actually pretty excited about this mainly because the tools look good and I know that the original Creature House developers are fantastic. For example, even while MS is not really supporting Expression 3, the developers from Creature House (now working for MS) still are. They are a great. I expect these products to be great as well and I would not judge them just because they will carry an MS label.