K2 studio has been the design canvas of choice with blackpoint for me for some time. Although I liked the experience of the Silverlight designer, I preferred a tool that allowed me to do more.
It got even better for with 4.5. I now use VS.NET to work with blackpoint processes. Since I work with both blackpoint and blackpearl this is the perfect tool for me.
VS.NET allows you to build your processes in Release or Debug mode. So, you can create your deploy packages in the chosen mode. The compile time experience is also better for a developer.