Actually, I've heard about that... UM2 is more designed for monitoring.
Background for choosing this - First, I don't have to monitor vocals.. I'm playing the piano/synth, so more likely to listen to separated instruments, especially sharp bass and drum kick.
Second reason is.. 50% of usage would be for stage monitoring, the other half for just listening to music - mostly jazz.
I'm kind of sad finding this website after ordering. I could've had better idea comparing different models.