Any time when we can put students in the role of teacher can be a benefit to everyone. I wouldn't say passion-based, student-driven learning is any less work than a more traditional model of instruction, but in this context, I could not image a better way to teach.
Choosing, thinking, reflecting, and sorting possible projects should be a career-long process. Good projects don't fade with time -- they get richer and more exciting for both teacher and student.
Great projects, on the other hand, are opportunities for learners and teachers to collaborate with those around them.
I've been using this site with a secondary ed class I'm teaching this summer. Lots of great information here! I took their PBL 101 course and really enjoyed it.