FWIU, Red has everything that BCC has but w/ a standalone user interface. Is the ease of using effects directly w/in Avid the only thing BCC offers that Red does not?
I've looked at the Boris website, and except for a few filters, Red seems to cover everything that BCC does. But perhaps I'm missing something, as the name "Motion Graphics Package" implies there's some non-overlap in the products' functionality.
Boris RED is a 3D titling and compositing package and can be used as a standalone compositor or as a plug-in to most editing systems. There are many tools in RED that are not in BCC, such as the Extruded Vector Trace tool or Raster and Vector paint tools or the built-in 3D Titler etc etc. While most users do not have a problem with the RED UI, there are some folk that prefer to remain in the interface of the editing system they are using, such as FCP or AVID. For these folk, the best solution is BCC. There are about a dozen filters in BCC that are not included in Boris RED, such as Pan an Zoom, UpRez, LED, Damaged TV etc. The reason that these filters are in BCC and not RED is that RED includes the BCC 4 filter set, while the current version of BCC is 5.
So ... why get the MGP? It includes the (substantial) feature set of the RED 3D compositor/titler plus the ability to remain in the host user interface for speed and ease of use.