I have seen and had several of these variants. The km -2XX series I think are all the same internal specs. I believe these were sold as a rack system. As you went up in the number(km205 vs km206 vs km209) you got more bells and whistles with the system.
They boast 150WPC and have a good punch. I am not sure I would really call it a 150wpc amp though. I think they sound pretty good. I am not sure what the differences in the preamps were - maybe that made a significant difference. I run my current one with a dennon pre.
I think the amps are well worth the $50 range, and maybe as much as $75. That would be resale value. As to utility, I think they are unkown sleepers.
My $0.02 worth