I myself have only played the WoW board game and let me tell you right now, it is a day long investment. I own the original board game aswell as the Burning Crusade expansion. I'm going to preface this by saying the game is alot of fun because what's next doesn't make it sound such. Set up will generally take the better part of half an hour, and learning, assuming you've got someone well versed in the rules with you, will take around 1 hour, should you lack someone with experience learning will take about two hours but that is done during the game. The game itself is surprisingly large and has many quests that make you go "I remember that!" while still providing a decent challenge. The
BC expansion adds the whole new continent and level to the whole thing which makes this game go on all the longer, to either the chagrin or delight of people who know how the game works.
One key thing to do is pick the class you're familiar with at the beginning so you can have a basic understanding of how things will start working, and while the board game isn't exactly like the MMO, there are some similarities in how the classes end up working out
Not sure if this was to vague as it's been awhile since I've played, but me and my friends still occasionally laugh about the times we've spent playing it, even years later