It is enough that when we started playing pathfinder after playing 3.5 since it's inception we thought it would be a piece of cake to transition, were we wrong! Almost nothing works the same. It was like relearning the game all over again! Yeah a lot of things are similar or the same, but enough isn't that you have to be on top of the changes all the time. Spell affects, classes, monsters, etc all work a little different and it is all based on a point buy system now. Tried using rolled characters at first. They don't mix well. The system is designed for a 15 point buy or a max of 25. Rolling gets you too powerful of characters too often. Three months in and we almost trashed it all and went back to 3.5! I couldn't even find my log in here and had to find a new one. Finally remembered my old password.