If you purchase a used bike there "may" be parts that need replacing
sooner than a new bike or at least a not so old bike.
As stated , ride them and see.
My guess is the Jamis has an Ultegra Front derailur and the rest is Tiagra. A Good shifter goes a long way such as 105 or Ultegra. Replacements can run $200 and up per pair.
Here's a suggestion, check
a) Shifters work smoothly up and down.
b) Cranks turn quietly
c) Check for cracks in the frame by the welds and joints.
d) Down tube or bar end shifter friction types last forever.
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