I remember that it took a while for me get used to the MM9 interface. We've all been playing the same basic interface for so many years, but one you get to the first dungeon you realize that the new game has the same heart as its predecessors.

You shouldn't have any trouble. The storyline is a bit more rigid than with the older games. When in doubt, consult your Quest log. It's more extensive than before. People get in trouble sometimes doing quests they haven't been given yet.

Your game will autosave just after entering an area -- not just before as in previous games. This might give you fits if your game crashes upon entering an area. This sometimes happens as a game advances and the savegames get larger. Make a habit of saving shortly before leaving an area, especially later in the game.

Be careful about accepting promotions. The process is different, and you (almost always) can't change your mind once you sumit a character as a candidate for promotion. Also, you can mess up your promotion assignments if you leave a promotion discussion by pressing 'Escape', so don't.