I dont have a 3 button, but the six button has a switch on it to change it from 6 to two button. From what I understand the switch on the three button is like what you said, turn on 3rd button or have a functioning select button, although I thought that the games that use 3 buttons are playable fine with a 2 button, and you have to use either the run or select button AS the third button. As far as the pad the three most popular are the three you stated, The Hori is said to be the best, I like the RX pad myself, but my thumb on the pad starts to hurt after an hour of gaming or so. I personally dont like the avenue 6, but its a great CHEAP way to get an extra 6 button pad. The hori looks like a SNES pad and is very comfortable and repsonive.