I have a pair of the Mackie SRM150's.
Great little spot monitor, good connectivity. Not too much low end, but that's kind of the point...
Louder than you would expect. It hangs in great with full bore stage bands (and that's louder than you'll ever crank a CM-30!) and sits on a boom stand with the boom on top (CM-30 don't tuck away as well, IMO)...
30 watts vs. 150.... Hmmmm......
They'll both sound good up to a certain point (and maybe the Roland, with a bigger speaker, sounds fuller at lower volumes), but if you ever play with real drummers, etc., crank it to the max and see which one peters out first.