Albinson & Knoll's 1601 stacking chairs  

Any fans of Don Albinson's 1601 chairs for Knoll?
Stacked or solo, it's a great little chair that seems very underrated and under-appreciated; especially when considering it had great optional attachments/accessories like armrests and stackable desk tops, and that this little chair sold so well that it kept Knoll afloat during some hard times*.
Seems like kind of an important chair in Knoll and MCM history, yet it's difficult to find much info about it (the internet seems rather quiet on the subject) and I find very few of them for sale online or off.
What's the deal with this chair? Are they somewhat rare/highly sought after? Is it's design considered mediocre to most? Did they age poorly/fall apart? Or, as seems to be a theme for Albinson, is the 1601 chair just out-shined by the designs credited to his collaborators (Eames, Saarinen, Shultz, etc.)?
Let's get talkin', forum!
Thnx,
*metropolis magazine