Unlike most manufacturers, Marantz components came standard with metal cases, and the company offered wood sleeves as extra cost options. I very much like the way the standard cases look, even though I can't say why theirs is the only fake woodgrain that looks cool to me. Ok, It's probably because unlike woodgrain applied over particle board, which gives the illusion of 3 dimensionality to the fake wood, it is clear that the Marantz cases are sheet metal, and that the woodgrain is an industrially applied pattern. There is an honesty to it. It surprises me that I prefer the sheet metal over the simulated wood skeeves that Pioneer and Sansui, to name two, used on all but their flagship models. For example, the Sansui 8080 is simulated woodgrain, while the 9090 is real. That's why I redid my 8080 case in teak.
Any Marantz owner could purchase a real wood veneer sleeve for their components. I don't know how much they cost in the seventies, but today (January 28, 2010) on Ebay there are a few for sale. The highest 'buy it now' price is $225, the average around $125. New reproduction cases cost more than many of the receivers they enclose!
They are not my cup of tea. While they are beautifully made, and look luxurious, to me they make the receivers look too bulky, and the way the aluminum front panel sits in the beveled front removes the perception of the faceplate as a 3 dimensional object, making it read as a 'skin'. They also in my opinion make the receivers look older than their seventies vintage...too retro for my taste.
All that being said, I have a beautiful WC-22 that will fit most Marantz 22XX receivers. My opinion is just that.