How does one get the Knights guilds?

you just need to join a crusade. i did it two times, never succed, and have already hospitalers guild lv3.

St. John's gives a health bonus. This can be very handy in far off provinces like the Antioch and Jerusalem. These get very large and unruly, so you need every edge you can get.

So if Yaz' website is correct, and there's no difference between St. John's Knights and Templar Knights, you want St. John's. I used to wait for Templars just because I liked their skins, but now I prefer St. John's.

If you get a Templar or St. John's offer, and don't want that guild, you can refuse it. The next turn you'll get another guild offer, usually the other kind. Keep in mind these often work best in Castles because there you can get additional cavalry upgrades. They stack very nicely. But it's also a good way to get great cavalry out of a city far away.

Finally, one important thing to keep in mind: once you accept a Chapter House, you can never get the other one in the game, so stick to the one you want and wait for it.

templars are described as more impetious than hospitalers so it make them worst:balloon2:

can you get several of the same type? (in different settlements)