I have the Jrok, the ArcadeShop and a 48-in-1. Moon Patrol on the arcade shop board SEEMS faithful enough to the original, but I am using the "modded" vertical hack version of the game. It still plays fine, though. The ArcadeShop board is a WORLD better than the -in-1 boards, as the sounds are correct and the menu is superior. The JROK plays the williams titles just as well as the original boards, due to the fact that it is using an original CPU. I have never ran my AS board as a horizontal to test how it plays the typical Williams games, so I can't give a DIRECT comparison answer on that one. I do know, however, that the AS board (while more expensive) is FAR SUPERIOR to the -in-1 boards when it comes to all of the old midway, nintendo and sega games. It is DEFINITELY NOT MAME based. I don't know if the -in-1 boards are, but it wouldn't surprise me, given the sound issues...
Lee