I don't mind the attract mode, prefer it on really as if I left the machine on I'd want it. Like PinBot they do not stay on if not in use.
The only annoying thing I find is the headphone jack has less awesome audio than the cabinet itself and you have to unlatch the whole thing to go in and pick which you want as it's a basic setup so one doesn't override the other so I've opted not to bother with it.
Robo Army is sadist, the way they attack reach or whatever is just slightly better so you just end up getting tagged even a bit by the dumbest of starter grunts. Top Hunter I dig enough, it's interesting. Blue's Journey is fantastic. My wife wants brawlers like TMNT on NES/SNES so I'm trying to find any kind of non-flat screen brawler types for her to dig into. Sengoku is an old fav, but it hasn't aged as nicely as some things have say Capcom or Konami made, but I have yet to ever play #3 (or 2 not on there.) Mutation Nation is on my try list. I pulled up Strikers 1945+ earlier ago, tough game even in world one and that's on difficulty 4.
What would you use to seal up the opened up cartidge slot? I saw someone made some paper art stencils of I guess something you could cut out up on flicker through a google image search. Other than that I found nothing and SNK even recommends capping the thing if it's not used.