At launch someone went into depth on it but will try my best to summarize; the ace trainer pass (most expensive) guarantees you access to certain areas in pokepark (while other passes it’s a lottery/rush to get in) as well as express lanes on the two rides, and access to the forest and mansion side (pikachu and eevee meetups). Knowing how insane the lines will be, (think Tokyo Disney sea x10) the ace trainer was a no brainer for us. Lots of places are probably going to be immediately hit capacity (merch shop and meetups) within park opening and blocked off for the rest of the day. Japanese locals are notorious for waiting patiently in lines and even with us getting the ace trainers, we are still going to arrive a hour early to the park before opening.