Different formats lead to different styles playing and non-playing.
PAPA - dedicated banks and less games involved in the tournament... so the rest of the facility is open for coin play. If you've never been to the facility, this is huge because you have a lot more freedom to play various games.
PAPA - 'play when you want format' - For qualifying, you pick and chose when you want to play and how much you want to play. Crowds can swell at peak times making waits tough, or play off times with little wait. No need to stay at the facility the whole time if you don't want to. This also means there is a lot more hanging out, tailgating, etc.
PAPA you play in the competition by yourself during qualifying.
PAPA - very hard to qualify... can play all weekend and feel let down you didn't make the cut. But there are side tournaments, etc. The main diversion (Classics Division) has become just as competitive as the main tournament tho.. lessening it's diversion value.
Pinburg on the other hand is a guaranteed play format. You also play in groups. This means at Pinburg I think you meet and mingle with a lot more different people than you might at PAPA. Everyone has a reason to meet someone! In addition, until the playoffs, everyone plays the same amount. You get a guaranteed # of rounds of competitive pinball.
This means you may drop as you play poorly, but you keep playing and keep playing with people in your same level. I think it's less stressful in that sense. Everyone is more in sync with a common schedule and cause...
However the # of people playing in pinburg means more games are tied up with the tournament and less games are available for walk-up play. Pinburg is actually a pretty grueling schedule of play.. making for long days on site.
So I find pinburg to be more 'fun' as a format... but has less flexibility and less free play around the facility. PAPA tends to be a more 'hardcore' format IMO, but has more freedom outside the tournament.
So I think if you've never been, and want to get the most out of the facility visit... PAPA. If you want to get the most play and meet a lot of people... Pinburg.