I recently had to replace my front derailleur and found that the braze-on really limited my options when it came to finding a replacement. Of course I'm in college and have limited income so it was important for me to find a good deal. Many of the FD's on ebay and other web sites were clamp, so I had to fight to get the braze-on ones. If I didn't have the braze-on I could just buy any one and buy a clamp adapter if necessary. Also, I couldn't fit an Ultegra FD on my bike because the braze-on was too low to get enough clearance on the big chain ring, even with the FD as high as it would go.