Im have two full size arcade cabinets my self. One Jamma based with old CRT Sony TV and one Mame with LCD Screen.
Im have two multiboards (138-1 GameElf multiboard and Pandora Box v3) as well 2 originals for the Jamma.
Im do guess Pi 2 performance was quite around same as that one im have. Here for Pandroa Box v3, its have various framerate/slowdown issues. Most games was playable throught, but some was not (one of them was Tetris Grandmaster 2, which was about 40% slowdown alltime). But in the end, im did really like this board, dispite issues. This was like excepted.
PS. Yes im have seen that arcade project. Im have still my iOS arcade, but is in the original state.