Quoted from dmarston:

I subscribed to all of these and have to correct you on a couple points.
Pinball Trader was started by Dennis Dodel, then taken over by Jack Simonton. I think that Tim Ferrante got some of their assets while he was publishing Gameroom, but Tim did not publish any PT issues. Under Dennis and Jack, PT was issued sporadically. The "Good Shtuff" was in the PT, not PGJ.
Gameroom was started by Dave Cooper, then went to Tim Ferrante, then Kevin Steele, and finally the Pinball Company. Under Dave and Tim, it came out on a dependable monthly schedule, as you say.
Loose Change was another 'zine that came out on a dependable monthly schedule, until some illness or family issue intervened. Once it got off track, it became extremely irregular.
Others, like Pinhead Classified and The Flipside, were irregular in their schedule.
.................David Marston