1f56bc31_ox_vs_App___SharePoint_Dragons__Farm
[0] When to use [Sandbox] Deprecated. Therefore, it’s unadvisable to build new sandboxed solutions. [Apps] Best practice. Create apps whenever you can. [Farm] 
Create farm solutions when you can’t do it in an app. See http://www.learningsharepoint.com/2012/07/20/sharepoint-2013-apps-vs-farm-solutions/ for more info.
SharePoint 2013: What to do? Farm solution vs Sandbox vs App | SharePoint Dragons
Farm