I have been referring to many articles that show comparison between SharePoint Sandboxed Solutions and Farm Solutions plus demos of Visual Web Part (Farm based) and Web Part (Sandboxed Solutions) under Visual Studio 2010 and it seems like Farm Based Development (using Visual Studio) and its deployment is far more preferred way by developers. Correct me if I'm wrong
Moreover,Sandboxed Solutions are restricted that Farm Solutions. Hence in what scenario a developer would preferred to develop/deploy solutions using Sandboxed way?
YOu can have more understanding about using the sandboxed solution from the below given link.
https://www.nothingbutsharepoint.com/sites/devwiki/SP2010Dev/Pages/SharePoint%20Sandboxed%20Solutions.aspx
In this link, there is a section for what is supported by Sandboxed solution and what is not supported by it.
Hope this helps.