STTNG is a great game, very deep. I have one (my second) and took the approach that I will only learn the rules by playing the game. I have always said that I would be buried with mine.
Once it's dialed in you have relatively few issues with it. The ball trough is usually a problem with the machine becoming confused about how many balls are in play, but it's not a difficult fix.
I did actually have trough confusion when I got the game. I cleaned all the optos but did not fix, I found that one opto was bad so I replaced it but did not fix....turns out one of the resistor legs was broken so I replaced that and the game has been great ever since