I have both, and really enjoy them. At one point I had them both in a corner (not optimal I know), and the kef q150s were too sloppy with the bass reflecting everywhere (even with foam in back). The DBR62 being front firing sounded much better (cleaner, more detailed) with that poor room placement. Though recently I reorganized them so that they are placed reasonably well in the room (not in a corner), so both have decent space around them. They both sounded great, though I ended up preferring the extra warmth of the q150s. Frankly I think the q150s have looser bass which in this room setup makes them sound warmer and more pleasing to my ear. The DB62s sound great too, maybe with a little more detail, and tighter bass, but I was more thrilled listening to the q150s in this room setup, even though I maybe sacrificed a little clarity.
My room is a square, small to medium size office with wooden floors, and the speakers are against the long wall with my desk against the opposite long wall. I was listening to mostly rock and jazz.