I am seriously considering buying a new carbon bike and I like the look of the Giant Defy Advanced due to it more relaxed Geometry in place of the Giant TCR Advanced 0. I was at my local LBS this arvo and the manager I was talking to advised me that the Giant DI2 is really a mismatch of parts. I told him the price of the 2012 model and he said if I can read between the lines (you pay for what you get). I have had a look at the specs and the KMC chain is the only non Ultegra part on there which a lot of manufacturers seem to be putting these KMC chains on their bikes. He did mention a Triathlete used Di2 and it broke down 8 times so he won't ever go back to it.
He mentioned his shop will be heading towards SRAM group sets on their bikes due to the double tap system
As I have never ridden sram before I can't comment on it.
Can I ask your thoughts on the Giant Defy Advanced DI2 in term of Ride comfort, Quality of parts, Durability and Less maintenance.
Can I also ask for thought on Sram bikes and how they differ from The Shimano non DI2 range
Not sure about the rest of your question , but also not sure if you realise that KMC actually manufacture the Shimano chains ? So , this KMC chain is , I believe , actually probably an upgrade from Shimano Ultegra chain.
Also , I ride lots of bikes ( i OWN MORE THAN A FEW ) and personally prefer Shimano ergonomics ( tried SRAM, but haven't tried DI2) but if I could afford Campy I think I would revise my opinion...
Double tap to the head is what the SAS are taught , not sure if I like it in bikes..