Breakingdown and cleaning is very much a pain in the butt. That is one of the main reasons we went with the M&P. The M&P breaks down like standard AR, M4,M16 frames with simple rear and forward takedown pins. The Mossberg has a million little screws and steps to break down. For our purpose we felt it would be to hard for our son and we wanted him use to the standard breakdown process for when he graduates to the 223 and 7.62.
Here is a YouTube link to a Mossberg getting disassembled...
http://www.youtube.com/watch?v=_bnJyl2ptbI