Weaknesses: This was the first generation Madone with funny shaped tubing. Perhaps the round tubes of the SL are better and more resiliant in a crash. The strength of the odd tube shape of the Madone is questionable.
For charging so much for a frame the Trek crash support could be better.
If you want to ride your roadbike then consider something cheaper that does not hurt so much to replace.
Bottom Line:
This review is of the 2004 Trek Madon 5.9, silver frame.
This frame is great if you are no afraid of carbon cracks. My frame cracked in the downtube in a road crash. The water bottle holes and increasing tube diameter create a weak spot as this is where the frame cracked. The crack proceeds up to the water bottle hole and around the bottom of the tube. Trek does not warranty such a crack as it was "imposed by a crash". The best Trek offers is a minimal crash replacement.