Can someone help me? I noticed Mike Tholen has often praised the Quantec reverb. I assume he is talking about the Yardstick room simulator that is on their website. But does anyone know about the Quantec QRS Reverb? Apparently it is 2 in/4out and looks like a 2 rack space unit. Anyone know how it differs sonically from the Yardstick? Is it also a highly desirable piece to acquire? What would be a good price for one? Do they still make them new or are they only available used?