Doing the flight control checks you'll sometimes notice the controls are slightly freer, or stiffer, than typical. Minor difference.
The non FBW a/c typically have to be trimmed, primarily rudder. Sometimes it's slightly right, sometimes slightly left. Some use the same trim setting at different speeds and some need retrimming as the airplane slows or accelerates.
Engines can have slightly different spool characteristics, especially off of idle.
Small differences, sometimes noticeable. Probably no different than if you drove 20 different cars of the same make and model, especially if they're 5, 10, or 15 yrs old and well maintained. They'd be the same, but not 100% the same.