I don't know if a week or so counts as necromancy yet, but I wanted to weigh in a little.
I think Puerto Rico is one of the five best games I've played ever, and I've played a lot of games. It's also one of the hardest. If you're playing to win, you need to do a lot of "okay, if I do this, then he'll will do that, and then she'll do this, but if I do this other thing then..." thinking. There are a lot of hard games out there that are hard for a lot of reasons. Puerto Rico is hard because there are many strategies to victory and just as many ways to screw your opponents, and a good turn will do both.