I'm working on a setup which wants to include the Microsoft.Web.Services3 (WSE 3.0) DLL. However, I typically do not like including Microsoft DLL's in our installs except by way of Microsoft's redistributables. There is both a developer and a redist install package available from Microsoft.
So, as a best practice, should I include the single DLL in my install or refer them to one of the WSE 3.0 installs (assuming they do not already have it installed)?
Usually, redistributing any of Microsoft DLLs outside of the redistributable package is forbidden by their EULA, so you might first want to check the appropriate EULA for that DLL.
Generally, I would prefer the redist package since that makes sure that it's correctly "registered" into the system, i.e. if you install a newer version of the redist it gets updated (like DirectX) or not overwritten if it's an older version (also like DirectX).