https://github.com/retropie/RetroPie-Setup/wiki/MAME
Mame4all-pi seems to have the best performance of them all but AdvanceMAME has support for more games. imame4all libretro can be compelling because it utilises RetroArch controller configurations.
so i guess with the pi1 you'll be wanting all the performance you can get, so go for mame4all-pi