I'm pretty sure it would work in any supergun or MVS. Almost anything JAMMA will unless there are special controls. The PC Engine is only 4 buttons, which is within the standard JAMMA limits, so it will probably just plug right in and work.
Its pretty nice looking, IMO, and not any more or less "hacky" than the TG-16 one. Both seem to have wires soldered directly to exposed expansion bus pins, which is pretty ghetto.
Both seem to have a lot of extra stuff on the JAMMA adaptor which makes me wonder if there was some kind of title select screen. There had to be some way to count the coins, limit the number of continues, etc. That New Adventure Island Franken-Hu is interesting too. Is the code modified to work as an arcade game, or is it a proto of the retail release? Maybe its just a %100 pirated copy?
Its hard to know this stuff since the whole idea of a PC Engine arcade machine never took off (to say the least) so we can only guess at what the stuff does and how it works until someone who actually plays their shit and contributes to the comunity buys one of the damn things, hooks it up, plays it, and tells us about it.
Currently at $55, this thing is a steal. The RGB hack alone is worth that.