I just bought an '06 LeMond Buenos Aires this past Spring. My bike is nearly identical to the '05 Zurich. The main differences in the Zurich are bottom bracket and crank are Shimano Ultegra vs. TruVative & Bontrager for mine. The wheels are the Bontrager Race Lites vs. the Race. I sat one afew Treks and the LeMonds and the LeMonds just fit my taller frame a little better (6'2.5" 215 Lbs). The original Race Luxe saddle did NOT work for me. The more I rode it, the more my posterior hurt. I switched to a Selle Royal Dargo and life has been infinitely better. I am sure there are better saddles, but this one was cost effective for me. I can't speak to the other bike as I have never ridden one. I can tell you that my bike is remarkably comfortable. This is my 1st road bike and I can't believe how smooth it rides. Even with the frequently terrible roads around here in the Buffalo Snow belt life has been good on this bike. I just finished a Century ride on it last weekend, and my bum (and other private parts) survived just fine and without pain. My legs were sore at the end, but that was to be expected.
For a point of reference I paid $1400 this past April for my new '06 Buenos Aires. The list price for the '06 was around $1800. From what I can tell on the web, the Zurich sold for about $200 more than the Buenos Aires back then. Add an other year of age to further reduce the price, and then add the fact that mine was new dealer stock that they wanted to sell, and had never been used. I am terrible at haggeling and quite frankly hate doing it. Given that, I would still bid a bit below the asking price. Used bikes lose value even faster than used cars. Otherwise you will have a very nice bike. The saddle the seller put on it may work for you, or may be just as uncomfortable for you as the stock saddle was for me. It is without a doubt the most subjective item on any bike.
Happy riding,
André