I have a bright red, 2002 Buenos Aries and I couldn't be happier with it- love at first ride.
The frame has a Reynolds 853 main triangle with 7XX stays (I can't remember if they're 731 or 725); very comfortable after 40 miles.
I bought the frame super-cheap in 2009, (painstakingly) restored it throughout summer, 2010, and have logged about 3K miles on it since (I only ride it in fair weather; my 'rain bike' & all-rounder is a Soma).