Now that I've methodically compared my 3GS keyboard with my iPhone 5's, it's obvious that my iPhone 5's keyboard is messed up. If you slowly press each key in two or three places, you can clearly see error zones on the iPhone 5 that aren't present on the 3GS. If someone else tries this, let me know if your worst keys are the "i" and "o" ("o" has a bigger touch zone than it should) and "a" and "s" ("a" has a bigger touch zone than it should). Also, it would be interesting to hear from people who can compare iPhone 4s running iOS 5.x+ and iOS 4.x. Hopefully, this is a software problem. Although I sort of doubt a keyboard this bad could have lasted the life of iOS 5.x without being fixed.