I went through some of my soundcloud mixes and after hearing them on the MSP5s, I think on the whole, I liked them, though all of the mixes with a bass instrument in them had the bass frequencies overemphasized.
Comparing what I've mixed with what I used for testing - Miles Davis's "So what" from his album, Kind of Blue - the upright bass in So What's mix was clearly audible on the MSP5s, but much more subtle.
Similarly, I pulled up Zanarkand from the Distant Worlds II CD, and the double bass in there is also audible, but sublime. Whereas my mixes they stood out very clearly, top and center.
So, I guess the VRM Box and AKG240MKIIs did a pretty good job considering.
Another aspect I felt is that my limiting and compression may be overly aggressive for some tracks, as they are a quite a bit loud compared to the commercial albums.
Gotta get my sample drive up!