Cdc: FWIW, I am upgrading to Ohm Walsh 2000s from Vandersteen 1Cs. In my room, with my gear, the 1Cs actually produced a different, but similarly 3-D soundstage as the Ohms. I was surprised by this, to say the least. I have noted above that the 1Cs actually extended into the room more than the Ohms. The 1C is a 2-way design with a minimal baffle, and open top plate. So, technically, it is not a basic dynamic "monkey coffin" design. I will repeat that the Walsh 2000s do a better job of localizing performers and maintaining a stable image than the Vandys did. If I keep the Ohms, it won't be because of an improved soundstage over the Vandys; it will be because they offer better imaging, almost no congestion at peak levels, amazing truth in timbre, and good low-level detail retrieval. IOW, the Ohm Walsh's are anything but a one-trick pony, which is how I think many people think of them until they hear them. The more I think about this, the more credit I give to the Ohm's design, which is as close to a single-driver design as possible, with a super-tweeter that comes in at about 8kHz, IIRC. Note that even the MBL, and, I think, the Duevels, use more standard crossover points in a multi-driver configuration.
That said, I have never heard a single driver design that I could live with. These were mostly at shows, but I found they sounded "peaky" in the upper mids and lower treble - exactly the range that I find very smooth on the Ohm Walsh 2000s. Although the bass reproduction was also dissappointing on these single-driver designs, I could, and do, live with subwoofers. Since my hearing is very sensitive in the upper-mid/lower-treble range, the Ohms provide a very enjoyable listening experience for me. They are not rolled off in this range, but I think they just lack the roughness and distortions that all but the most expensive crossovers seem to exhibit. YMMV, of course.