Hi,
Reflectivity is a function of water and ice in the atmosphere. This can be caused by convection or also non-convection created precipitation. The micro-physics scheme deals with non-convection water in the atmosphere and obviously differences can be seen.
I do not have the resources to perform a proper validation of the model results so only trial and error over a few months by looking also at the weather radar will give some clues on which of the 2 schemes is better. At this point, I have no idea!
David