I've heard people describe San Juan as Puerto Rico's little brother. What's actually the difference?
- How is the game-play changed?
- Is it any easier to teach new people?
- Is it worth buying if I already have Puerto Rico?
Game Play Differences
While the games are thematically the same, and San Juan was designed as the "card game version" of Puerto Rico, the gameplay is actually quite different.
Teaching the Game
San Juan is definitely easier to teach to new players, though I wouldn't say massively so. However, it is much easier to teach how to play well than is Puerto Rico, and so is more forgiving.
Is It Worth Buying?
I absolutely consider it to be worth buying. If it's like any game, it's really most like Race for the Galaxy (see below for inside scoop), but a much lighter version. It's much faster to play than Puerto Rico, and is actually quite fun with just two players, something that can't really be said of Puerto Rico. The two games are so dissimilar in play style and feel, you'll never mistake one for the other in any way, even if you played them back-to-back.
Just a short bit of gossip about San Juan and Race for the Galaxy: the story goes that when Alea Games saw the (comparatively) great success of Puerto Rico, they started hinting around that they were interested in a card game version. One submission was a game very much like Race for the Galaxy, though many years earlier. The Race-like game wasn't selected as the winner, but the eventual game, San Juan, turned out to have incredible similarities, including the cards-as-resources, cards-as-money, and cards-for-their-face-function game concepts. Whether any ideas were copied or not, in the end Race needed a fair bit of redesign to make it less like what San Juan turned out to be.
One is played with cards (SJ) and one is played on a board (PR). San Juan is certainly easier to teach and far faster to play (not to mention setup). It's a quick fun game. It's still rich in strategy in the way that Puerto Rico is, but, it lacks some of the complexity, depth, and nail-biting-ness that I've found in a good Puerto Rico game. Oh, for a list of discussion threads on BGG that have gone over this, see here.
The only thing these games have in common is the artwork, theme, publisher and role selection mechanic. Alhough with similar themes (building your infrastructure and producing and selling goods), most of the game mechanics are completely different. Basically:
So answers to your questions:
P.S. They are both really good games, just really different.
San Juan takes a couple of the concepts from Puerto Rico: building assets that then provide points and resources or some other benefit, and per-turn role-picking, and implements them in a card game with similar imagery and item names to Puerto Rico. Aside from the 5 role tokens, San Juan is 100% cards.
The closest I've come to playing Puerto Rico was about three turns on BSW, but it is definitely a much more complex game than San Juan. In addition to building structures, you have to manage placement of workers on them. If I understand correctly, produced resources can't be turned immediately into new buildings or workers, but must be shipped off first, shipping be another mechanic not found in San Juan. I'm guessing there are more differences, but as I said I haven't played a full game of Puerto Rico yet.
To boil it down, San Juan is a simple card game, and Puerto Rico is a (very?) complex board game.