You'll find a decent amount of past discussion on map testing on this forum, but my brief summary is that I think it's not incredibly useful for either instructional purposes or progress monitoring. I don't think there are enough student responses in any particular skill area for it to be diagnostic - for example, if you're assessing cause and effect, it's unlikely that there would be more than one or two items representing that skill, which is too little data to determine a strength or weakness in that area. It's also given too infrequently to be useful in a progress monitoring capacity.
However, I will say it could useful for program evaluation purposes - examine average scores from groups of kids on the class, grade, building, and district levels to determine effectiveness of an instructional program. I think it'd comprehensive enough and with adequate psychometrics to support use in aggregate. However, any classroom teacher can probably tell you multiple stories of point loss, 30 point growths, etc which indicates less than adequate psychometrics for decision making on a student level.