The ramp entrance IS different, it is a sharper angle where it meets the playfield, and actually a narrower shot because of the metal sides.
Add to that the hinge at the top, that can get a little slop over time, and take energy away from the ball, and you have a good amount of rejected shots.
The ball also rolls back down the ramp differently, it just kinda plunks back down the lift ramp (again due partly to the metal sides), where the pro smoothly comes down and often gets a little kick off the post at the entrance.
Finally, when it lifts to bash the BG, it kills the flow, and doesn't allow for putting the inlane X on big money shots sometimes.
Add it all up and that is why people "whine".
Enjoy yours, I'm glad it shoots without issue, but many of them do not, and perfect shots that brick and reject right back to the drain are reasonable complaints IMO.