ArcMap .NET add-in vs. classic COM extensibility

Discussion created by mtfresh on Jan 11, 2013
Latest reply on Jan 25, 2013 by vbmart
I am working on a project to replace an old ArcView application that used custom Avenue scripts.  We originally chose to use the new add-in model to create custom components in C#.  However, we discovered another group may be developing application framework customizations using classic COM extensibility.  (The terminology can get a little confusing and nebulus, so to be precise, I am talking about these two methods:  Add-ins and COM Application Framework Customizations.)

I would prefer to stick with the newer add-ins if they can play together nicely with the other group's COM extensions in the same ArcMap instance.  The documentation says that add-ins don't support all the functionality of the COM extensions, but they appear to provide everything we will need.  Plus, they seem simpler and don't require all the COM registry entries.

Questions:  Are add-ins the preferred method for new development?  Will ESRI continue to support the older COM extensibility or is the plan to phase that out?

(Yes, I'm trying to justify using add-ins with something more substantial than just my personal preference.)