I have had 8 or 9 of them, or maybe more, LOL... I think the most I had setup next to each other at one time was 5. Great layouts, very different than typical machines from that era. Rules were just so-so, and the playfields were painted on by Crayola unfortunately. I am down to one System 3 now (R911), but will always pick one up when I come across them as the deal is usually too good to pass up.
I dont have a favorite, but 1812 lasted here longer than any other game in my collection.