Pathfinder 1e vs 2e

I've played quite a bit of Pathfinder 1e and have been GMing Pathfinder 2e almost non-stop since it came out. I'd say the main differences are that Pathfinder 1e is much better at being a "simulator" and Pathfinder 2e is better at being a "game."

1e has rules for everything, and gets really crunchy. There are precise rules for making any kind of jump you could imagine and very little ever has to be left up to GM discretion. The economy for mundane and magic items was meticulously written, to the point where entire campaigns can be run about being a simple merchant. That being said, game balance between classes is almost non-existent. Martials are strong in the early game and get completely eclipsed by spell casters in the late game, while Gunslingers are always insanely OP because, you know, guns in a fantasy setting. This tracks with being a good fantasy simulator but doesn't always lend itself to fun gameplay.

2e is less crunchy (though still much crunchier than D&D, in regular Pathfinder fashion), opting to be less precise about ultra-specific rules cases and instead focusing on the meat and potatoes of what it takes to play the game, leaving the GM to resolve niche cases where the rules are unclear. There are thousands of character options and an extremely flexible multiclass system which feels far less punishing than multiclassing in any other system I've played or ran, and all of these character options are very well balanced, to the point where only the most specific min-maxed builds are able to edge out over the average player. The system's math is extremely tight, making every single +1 and -1 matter, and even these bonuses have been condensed and simplified from the crazy amount of math from the previous edition. The system's three-action-combat mechanics give players more flexible combat turns that end up being pretty unique from battle to battle, helping to reduce the monotony of combat that plagues most TTRPGs.

Personally, I prefer 2e. It's also vastly easier to get into as there have only been about a year and a half of published content for it as opposed to the ten years of published content (and powercreep) that has been released for 1e. That being said, there has been so much packed into this year and a half that you will not have to worry about running out of things to do - we'll be getting four new classes this year (bringing the total to 20), at least 20 new multiclass archetypes (bringing the total to over 100), two new three-volume campaigns, one new six-volume campaign, a republishing of Kingmaker for 2e (including new content from the Kingmaker video game, as well as books for converting it to 1e or D&D 5e), a couple new (as of yet unannounced) standalone adventures, and multitudes of one-shot scenarios for the Pathfinder Society organized play (that can also be fit into campaigns outside of organized play). Not to mention several books on lore, including regions previously unwritten about in the Golarion setting.