I've played a bit more Pinball Hall of Fame: The Williams Collection, and also another in the series, Pinball Hall of Fame: The Gottlieb Collection. I like the Williams tables better in general, but some of the Gottlieb tables are pretty cool. The Gottlieb game has some problems, though: it is impossible to set a high score or complete a goal while playing the tournament mode, so if I just want to play through the tables without having to select each one individually, I have to forgo high scores; the tournament always plays through all the tables, so it takes a while, whereas the Williams tournament randomly selects a configurable number of tables; finally (for now), the high scores on the Gottlieb tables are quite low and easy to beat, and the goals are pretty simple to complete.
As for progress, I've got 999 credits on the Williams game, which is the maximum. Sadly, there doesn't seem to be anything I can do with those credits since I've unlocked free play on every table, but there they are, in any case. I've also set various high scores, but I'll have to check on them if I want to make a list, since I don't really remember which.