I voted 50/50, but I could lean more towards game. IMC, I know where the PCs are going. I know the route, more or less, that they'll have to take. What I don't know are the details. It's like saying they'll go from Boston to Los Angeles and pass through New York, Chicago, & Salt Lake City, but everything else is yet to be determined. I've realized I enjoy DMing not because I like telling a story, but because the players constantly make me discover new things about my own setting. All that said, I don't waste alot of time with new PCs. We have one guy playing for maybe 2-3 weeks, replacing someone who temporarily can't make it, and rather than waste time setting up a big intro we just played.