Two important considerations are the number of functions the DCC system has and if the system has CV read capabiltiy.
The number of functions let you control various locomotive lights (headlights, marker lights, ditch lights, etc) and sounds (bell, horn, etc.).
Changing CV decoder values lets you move functions, change the locos address - to say the road number, make speed tables to match locos in a MU, etc. It is VERY nice to be able to read back any change (write) to the decoder's CVs to verify that the change "took" and was correct.
To compaire systems, you might look at the great table on Tony's Train Exchange website:
http://ttx-dcc.com/
(seems to be down right now, so I can't link you directly to the table)
IMHO, the MRC system is limited - you can get a better system for just a bit more money. You might compare the Atlas Commander and the Digitrax Zephyr (which is my system).
Good luck!