I've the defi 2 & absolutely love it , the frame I believe is a composite material , if I'm truthful I only chose the 2 as I liked the colour combination , I thought when I went to purchase mine that you had a choice of the different models & the different colour combinations but that's not the case , pop along to your local giant bike store I did & the service that I recieved was fantastic , the bike fitting service they offer was great also