I have read the blurb on the Giant website, but what is the real difference and can an average rider feel it ? sounds like the Composite just has one less layer of outer carbon ?

Advanced uses higher quality and lighter carbon (700 as opposed to 600 or something) than the Composite. The SL is higher quality and lighter again. I asked this very question on Friday at the LBS.

What Bull & Bladder said really.

Advanced is stiffer as well.

As for the average rider, i’m doubt it unless you already ride a composite Giant.

thanks for info. I recently bought a Defy Composite and love it, just curious about the differences