HI,
I found a used 2001 CAD 4, and its been a great ride so far, had to replace the wheels due to spoke failures, due to miles age and my size.
and the right front shifter rather pricey..
Its pretty nice, My LBS says aluminum bikes are pretty stiff, Ive notice my ancient steel bike is a softer smoother ride.
On a really rough surface its amazing how much vibration you can feel thru the frame.
After you start riding longer distance your joints will become a little sore from all the vibration.
Fit is paramount to enjoying distance.If it don't fit right you can't ride due to pain in arms, legs and your bumm.
Doug
Used bikes can be money pits due to wear and tear things like wheel sets, gears,chains, brakes, shifters.I even had to have my rear gears replaced on the steel bike,, another problem has it crashed most people selling their bikes forget to mention they dropped it going 25mph on a hill some forks are hard to tell when they are cracked.
Ditto for the frame.