I found my Trek 520 by accident, I was looking for older road bike to use on a ride. I found an awesome charity in the St Louis Area.
www.bworks.org they are a 100% volunteer organization that has a summer program for at risk kids. At the end of the summer program the kids that complete it receive a bike as a reward. They survive on reselling donated bikes, I though I could find a bike and support a great charity. I went there on a whim and found a used Trek 520 in really good condition. So $500 later it was mine, I thought I was only going to use it for a ride I was planning on the Katy Trail. I have a trek Madone that I have been riding for the last couple of years. So I was suprised at how much I like the 520. I have had it since May 2013 and I have ridden it 1000 miles and now the only time I ride the madone is for racing. Here is picture from the day I brought it home.