One thing I can say about the Orbital Modulator is that I haven't been able to clip it yet. I saw someone say the Phase 90 can be clipped with an active bass if you're digging in, and I have an active bass and I frequently dig in when playing.
Overall Orbital Modulator seems to add a "tinny" tone to your sound, which is a problem for me with the chorus/flanger side, but for some reason doesn't seem to bother me as much with the phaser side.
For all effects I pretty much use the lo-retain at noon, which as far as I can tell preserves your low end, but allows for enough of the effect to get through. I'm finding if you go higher than noon, in general the effect seems to be lost or too subtle even on higher strings.
Feedback will really increase the effect, but it also seems to add more of that tinny sound. Hard to find the right balance. I have a Bass Boost Chorus on the way, I'm just wondering if I like the phaser side of the OM enough to keep it just for that.