I started playing role playing games with a friend who started running a game based on photocopies of photocopies of Gary Gygax's hand-written notes. I'd been playing war games for a few years, and enjoyed D&D a lot as well. Over the years, I've run or played in games using all sorts of systems. Most of that time I've run a game based on the original D&D 3 book set and pieces taken out of its supplements and the very early D&D magazines. Other than original D&D (OD&D), the original Runequest has been my favorite set of game rules.
When D&D 3.0 was being developed, friends of mine were play testers. The revamp of the game sounded very, very promising. AD&D had become far too Byzantine for me, I skipped AD&D2 entirely. When the d20 rules for D&D3 came out, I started a game using them. I was excited, I was ready for the change and wanted to have a game that'd roll along as easily as OD&D but be somewhat more fleshed out.
Unfortunately, things never really gelled. The game just didn't run all that well for me, and my players were ready to give up. About that time 3.5 came out. Hopes high, I checked it out. Unfortunately, it took what wasn't working in 3.0 and made those things worse, not better. It was more complicated and institutionalized the power creep that had already entered the game. I went back to OD&D for my fantasy games (for SF I was using the original Traveller rules I bought in 1977.)
The appeal of what d20 represents was still there, but at the table the game just wasn't working for me or my players. The system made it about impossible to bring in new players, the life of any long-running game. With OD&D I could get a new player in the game making confident choices for their characters in an hour or less. Yeah, I was writing my own adventures and content no matter how little time work and the rest of life left me. Yeah, players never quite knew how things were going to go when they were outside combat and I was making up resolution systems for their actions on the fly. But we could jump in, play, and have fun easily and quickly at the table. I could write really simple software to help me generate encounters and otherwise prepare for a game. I had over 30 years worth of notes backing up my game.
Then came the announcement of D&D 4.0. No big deal. I'll just keep rolling along with OD&D.
But some folks weren't ready to give up on d20. It had worked for them. The "ecosystem" thing that the OGL promised had actually happened. That ecosystem thing was something I wanted part of, in spite of my problems with d20. Then leadership happened. The folks at Paizo decided they weren't just going to give up the stake they had in d20.
I downloaded the Pathfinder RPG beta document, and immediately liked what I saw. Non combat skill rules were simplified. The rogue/thief class had some power back. d20 rules problems were settled with sensible corrections. As a beta document, it didn't have all the introductory material that would be expected in a finished product, but it definitely was a big step toward closing the gap between me and d20. I ran some skirmishes with small groups of players and played around with the rules solo. It was encouraging.
Another plus was that the core rules would be published in 2 books, a rulebook and a book of critters for the game. Getting soaked by the tradition of putting things in 3 books was getting old, especially when five hundred add-on books follow, and other systems were regularly coming out with a single core book. Add to that that with border art, incidental art, and other foo-foo each page of each book dedicated less than one third of its space to actual rules, and it was time for a revolution.
I picked up the Core Rulebook as soon as it was available at my friendly local game shop. I bought it to read, not to play. I had an active Traveller game going using the new rules from Mongoose. But, as with the beta, I ran some solo stuff to sort of try out the rules and I ran some simple skirmishes with my daughters just to get some experience with live players.
I liked the changes Paizo had made a whole heck of a lot. The changes are few, and subtle, but the effect on play are tremendous. It's what d20 should have been.
Then the Bestiary hit the streets. I picked it up, too. The free previews had spurred my interest, plus this way I'd have a full set of core rules in case I wanted to play for real someday. Not that I couldn't have used any other d20 book of critters, like my D&D 3.0 Monster Manual. But among the other things I'd liked, a set of sample stats for a typical critter is a part of each listing in the Bestiary. If you don't want to have to roll dice for each random encounter, now you can just use the prefab creature straight from the book.
Finally, my daughter decided to take a sabbatical from running her Rules Cyclopedia based OD&D campaign. Her players wanted to keep their characters going, so I agreed to pick up the game. My little skirmishes and pseudo-encounters had given me confidence that I could run Pathfinder, so I converted the characters and started running a Pathfinder campaign.
I took advantage of the d20 ecosystem and pulled "Hollow's Last Hope" from the internet, touched it up, and put it into play. The first session I used a few OD&D mechanics to keep play rolling (my players didn't even notice.) I looked up the rules I was fuzzy on between games, and the second session went even better, and hewed closer to the rules as written as an extra added bonus.
By the third session it was as easy for me to run the Pathfinder RPG as it is for me to run OD&D. This is as opposed to D&D3.X, which was still a rough struggle for me even after a year and a half. Granted I have the D&D3.X background as I'm coming to Pathfinder, but really that's not the issue. Any more than my Runequest experience affected my ability to run Lejendary Adventures or any of the other skill-based systems. Rules either run well or they don't.
By itself that's good, but what really sells me on a game system is how it affects the players. That's what sold me on Mongoose's Traveller after over 30 years of running "Classic Traveller" (which I still stir into my Mongoose Traveller game.) The players felt more empowered by MGT, they got into the characters and adventures faster and more deeply. Classic Traveller is still great, and it meshes well with MGT, but when I run a science fiction game it's Mongoose's rules that are the core now.
Pathfinder had the same effect on my players relative to OD&D. The non combat skills set now assisted the players, rather than confusing them. There is enough definition to make them feel empowered, but its simple enough they aren't overwhelmed or confused. It's enough, and not too much. That's hard to do. Paizo did it.
A word on the art. Art has a pretty strong effect on me when I'm reading those rule books. I try not to let it happen, but it does. As much as I like the Mongoose Traveller rules, the art puts me off. I end up covering it with my hand so that I can read the rules on many pages. I roundly hated the art in the TSR d20 books. The border art, the character art...I hated it all.
I dislike the Paizo art a whole lot less. It still comes across as kewlio, but it's not oppressively so. The technical execution is definitely a big step above the TSR book art. Hackneyed as the characters and scenes are, I roll my eyes at it a lot less than I do the TSR art. It's decorative, rather than obnoxious. The TSR d20 books would be better as nothing more than black text on white pages. The Paizo books would be diminished by the loss of the art.
In a world where over the top, overly embellished fantasy art has become de rigeur, the Paizo art is the best of the breed I've found. It's not my cup of tea, but it doesn't make me grit my teeth and cover half the page with my hand as I try to get some rule into my head.
Bottom line, I like Paizo's Pathfinder RPG. A lot. I like it more the more I use it. I feel like the money I've spent on the game (aside from the GM screen*) is well spent. My players are having fun, even the one that doesn't like fantasy games. I can run a smooth game that swims along nicely. The power levels are high compared to D&D3.0, but at least they're well balanced and so far appear pretty well stable. Thumbs up.
I can also recommend the Game Mastery Guide, though it's not essential by any means. I got it strictly as a luxury, and it's been a good read. If I ever feel the need for adding a bit more structure to my cities, I'll probably use the material in it. Most of the material in it is aimed at a newer DM, or one moving from using prepublished modules to buillding their own campaign. Even as a DM with over 35 years of experience I'm enjoying it, but it hasn't really affected my game yet.
Speaking of art, the cover almost put me off buying this book. The guy on the cover looks like he's the Munchkin Your Mother Warned You About. Again, the art's technical execution is excellent, but the subject it trite and overworked. But you know what they say about books and covers.
* Now that I've said that I don't like the GM Screen, I guess I'd better explain it. The construction and materials of the GM screen are top notch, but as a game reference aid it sucks rocks. The Paizo people would do well to go back and look at the contents of the GM screen for "The Classic Dungeons and Dragons Game" box set. It's the most useful GM screen ever made, bar none.