There are other titles where arcade or keyboard has a preference (to me) in terms of game play. Rather than name all, it's a given that this is one golden reason why arcade vs MAME scores should never be co-mingled in the database.
It's not just how the title plays between the two (such as "Kangaroo" allowing gorilla-leeching in one but not the other)...it's also the benefits of using one controller type vs another.
In some cases the original arcade controls are more difficult for logistical reasons...anyone who has seen the control pad for "Crazy Balloon" knows what I mean as a keyboard is infinitely better. But playing a vector-graphics game like "Tail Gunner" with a mouse is far better than the arcade original, especially since on MAME you can change the analog setting speed whereas the speed is fixed in the arcade classic.
However, keyboard players face the challenge of having the directional controls on the RIGHT side of the keyboard whereas playing the arcade original has the movement controls on the LEFT side. I noticed this with "Scramble" although after much practice I am adept at using either for this specific title.
There are too many examples to cite here as this is a much broader discussion. But for "Up'N Down" in particular, seeing as how I have no access to an arcade original, getting used to keyboard standard directional arrows for diagonal movement was a necessity for me. Takes some getting used to but now it is second nature to me.
Also makes me wonder whether I'd fare as well if I were to try the arcade original after getting used to keyboard controls for this title. Who knows ?