I'm looking for thoughts regarding the purchase of a used bike when it comes to component age - particularly derailleurs but also any other components I should be aware of. I have seen comments similar to the following: a new Shimano 105 is as good or better than the Ultegra line from a couple years ago.
Is this statement true? Is there a place I can compare specs/performance of component models from different years?
I've been shopping many used bikes on CL and Ebay. For an example to this topic, I'm looking at a 2006 Specialized Roubaix with Ultegra components and ~1600 miles on it. If I was to buy new, the 2008 Roubaix Elite uses 105s instead. Have design advances made the 105s of today technically as good or better than the 2 year old Ultegras or am I in better shape with the higher line of components of 2 years ago that have not been heavily used?