WAS & NetWeaver Dev Studio vs IIS & VStudio.net with PDK for .net

Hello

Both have tha same functionallity or exist advantages for use the WAS & netweaver devstudio instead IIS & VStudio for develop applications for SAP?

In my organization the developers are very experienced with Microsoft's development tools, and actually we have several web applications that use the SAP.net connector and C#

They don't have experience developing applications with Java, but if exist a good reason to do that, then they can start to learning it.

Thanks in advance