Damn, I wish someone had given me that advice prior to my purchase. People over here have been raving about the Brainwavs non-stop. Theres definitely a difference in the sound. just not a good one IMO. I gave it a few days of listening, just cant get used to the unnecessary bass hump and the narrow soundstage, so I've shifted back to the focus pads for the time being.
YMMV, and with my particular pads/cans:
the soundstage does take a small hit, but it's almost negligible. 5% tops. You might be confused with the fact that the soundstages relative position changes a bit, it moves closer to you/inside your head, width having the beforementioned small reduction, but height/depth remains the same.
With me, the bass "hump" you mention translated to an increase in sub-bass, combating any signs of roll off in that department - increase in quantity increased the detail in the timbre in the low end, added some texture there, I don't mind.
Also, the treble problem I was having, was eased a bit.